314 Contributions to Physical Geography. 



that which before existed. A new cone is likewise soon formed 

 round the comparatively small opening which remains, and 

 through which stones and ashes are continually ejected. It 

 always assumes a regular form, sloping inside and outside at 

 an angle of about forty-five degrees. Its height at present is 

 1320 feet, its diameter at the base 2800 feet, the hollow in- 

 side 650 feet deep, and the inferior orifice there not more than 

 70 feet wide. At every great eruption this cone, which in En- 

 gland, in France, and over the greatest part of Europe, would 

 be looked upon as a very good- sized mountain, falls back again 

 into the fiery abyss from which it rose. 



The total height of ^Etna, cone included, taking the me- 

 dium of various barometrical observations, and allowing a dif- 

 ference of 9$ inches of mercury (French measure) between the 

 sea-side and the top, is nearly 10,200 feet French measure. 

 The difference of temperature between these two extreme points 

 is about 40° of Fahrenheit. Although ^tna be fifteen or six- 

 teen hundred feet above the line of perpetual snows, in this 

 latitude (37° 51'), snow in summer is only found in a few 

 sheltered places ; especially in the great crater itself, where it 

 remains throughout the year. The whole country is supplied 

 with what is here deemed one of the necessaries of life from 

 this natural ice-house. 



The whole of ^tna, as far as it can be ascertained, consists 

 of accumulated lava, scoriae, and ashes, the analysis of which 

 can alone throw some light on the nature of the substances 

 operated upon by the subterranean fires. It has often been 

 made ; and the substances found to predominate are, I believe, 

 silica and alumine* 



2. Account of the Large Chestnut of Mount ^tna. By L. 



SiMOND.* 



liCaving the lettiga and baggage to follow the direct road 

 or path to La Nunziata, we went on horseback with a guide 

 over the mountain to see the celebrated chestnut-tree, called 

 Castagno di Cento Cavalli, because 100 horses might stand 

 together under its shade. We rode ten hours for that pur- 

 pose over rugged tracts of lava and precipices, requiring the 

 * From Tour in Halt/ and Skill/. Lond. 1828. Pp. 310, 513. 



