198 



^TNA AND VESUnuS. 



From this time it rapidly diminished in size by 

 the action of the waves, and on the 25th of August 

 was only two miles in circumference, and on the 

 Sd of September three fifths of a mile round and 

 107 feet high, with a crater 780 feet in circumference. 

 On the 29th of September its circumference was re- 

 duced to about 700 yards, and was composed of in- 

 coherent ejected matter, scoriae, pumice, &c., form- 

 ing regular strata. Towards the close of October 

 no vestige of the crater remained, and the island 

 was nearly levelled with the surface of the ocean, 

 except in one place, where there was a small sand- 

 bank. At present there is a dangerous reef of vol- 

 canic rocks, about ten feet under water, where the 

 island formerly stood. 



Mtna. — The eruptions of ^tna date back among 

 the earhest records of history. The first on record 

 is in the year 480 before Christ. This was followed 

 by others, 427 and 396 B.C. Then, after a lapse 

 of 250 years, we have four more, between 140 and 

 122 B.C. Then, after 66 years of rest, we have three 

 others, between 56 and 38 B.C. Seventy-eight 

 years then elapse before another, in the year 40 

 A.D. A pause till 251 A.D. Another till 812 A.D. 

 A third to 1169 A.D. Since then, in the 12th and 

 13th centuries, we have had 3 eruptions ; in the 

 14th, 2: in the 15th, 4; in the 16th, 3; in the 17th, 

 8 ; in the 18th, 14 : in the 19th, 6 eruptions. The 

 number of eruptions in Iceland during the last nine 

 centuries is 42.* 



Vesuvius, — At the time of Strabo, Vesuvius offer- 

 ed no other indications of its volcanic character than 

 might be inferred from the analogy of its structure 

 to other volcanoes. The ancient cone was of a very 

 irregular form, terminating with a flattish summit, 

 where the remains of an ancient crater, nearly filled 

 up, had left a slight depression, covered in its exte- 



* Daubeny on Volcanoes. 



