THE COASTS OF SICILY. 75 



and to the west and north by high mountains of 

 sandstone and calcareous rocks. A spur of this 

 latter chain advances towards Etna, where it is soon 

 lost beneath the volcanic tufa. From this point 

 two small streams proceed the Onobola and the 

 Simete which encircle the base of the mountain, 

 marking almost exactly its limits, and transforming 

 this burning focus into a veritable isthmus. 



Isolated in the midst of its well-defined domain, 

 Mount Etna rises in a pyramidal form to a height 

 of nearly 11,000 feet*, and measures at its base 

 from thirty to forty miles in diameter. This vast 

 extent of surface, and the facility with which the 

 eye can embrace every part of the mountain range, 

 give to Etna a very different aspect from that 

 which one might have expected. There is nothing 

 menacing or abrupt in its appearance; and as the 

 eye follows its broad and finely developed outline, 

 which seems to rise in gentle slopes to the culminat- 



* The absolute height of Etna varies with that of the cone which 

 terminates it, and as the latter is modified by every eruption, new 

 measurements are frequently required. Two distinguished English- 

 men have obtained, by very different methods, results differing only 

 by one unit, for the elevation of the highest summit before 1835. 

 Admiral Smyth obtained his result by trigonometrical operations, 

 according to which, the height of the mountain was 10,874 feet 

 Sir John Herschel by the use of barometrical observations obtained 

 10,872 feet. We see therefore that the mean of these two results 

 would be about 10,873 feet; but the summit which yielded these 

 results no longer exists, and it would appear that the actual height 

 scarcely equals that of another point of the crater, which was found 

 by the same observers to be forty-three feet lower than the former. 

 The height of Etna at the time of our ascent must therefore have 

 been about 10,830 feet 



