ELEVATION OF JORULLA. 195 



deck, and several tons' weight of it must have been 

 thrown overboard ; for, though an impalpable pow- 

 der when it fell, when compressed it had consider- 

 able weight, a pint measure of it weighing twelve 

 • ounces and three quarters." 



During this eruption many thousand inhabitants 

 were destroyed ; vegetation was completely killed ; 

 the sea rose twelve feet higher than it was ever 

 known to do before, and violent whirlwinds pros- 

 trated everything before them. 



In May, 1759, the plain on which the volcano of 

 Jorulla now stands was highly cultivated, and cov- 

 ered with indigo and sugar-canes. In June follow- 

 ing, hollow subterranean noises were heard, ac- 

 companied by earthquakes, which lasted fifty or 

 sixty days. By the month of September tranquilli- 

 ty seemed established, but on the 28th and 29th of 

 this m.onth the subterranean noises again began, and 

 the ground, over an area of three or four square 

 miles, according to Humboldt, rose up like a blad- 

 der to a height of 524 feet towards the centre of the 

 present volcanic district. Fragments of rock were 

 thrown to a great height ; ashes were scattered far 

 and wide ; and the light emitted was seen at a 

 great distance. Two streams of water which ran 

 through the plain precipitated themselves into the 

 volcanic vent, and assisted, by the decomposition 

 of their waters, the fury of the eruption. 



Submarine Volcanoes. — The whole of Iceland is 

 believed to be a volcanic mass which has been 

 projected from beneath the ocean. In January, 

 1783, a volcanic eruption, attended with flame, rose 

 through the sea about thirty miles from Iceland ; 

 several islands were formed, and a reef of rocks 

 now exists where they were formerly situated. 

 The flame lasted several months, during which vast 

 quantities of pumice and light slags were washed 

 on shore. Another submarine eruption occurred 

 near the same island in June, 1830, which resulted 

 in the formation of an island 



