Natural History of Volcanos and Earthquakes. 261 



During the violent eruption in the low country of Skaptar 

 Jokul in Iceland, in 1783, which suddenly brought up the most 

 enormous masses to the surface, the lava burst forth at three dif- 

 ferent points, more than two geographical miles distant from one 

 another, and spread over a surface in the plain,* which is suppo- 

 sed to equal in extent sixty geographical square miles. This 

 mass is so considerable as to surpass in magnitude that of Mont 

 Blanc.f Under almost the whole of Iceland, there is a volcanic 

 furnace, which communicates by many apertures with the sur- 

 face. The masses of melted matter, therefore, seek an outlet at 

 various points, and many places are mentioned, at which the lava 

 has only been ejected once within historical times. The vol- 

 canic phenomena are not confined to the island alone, they also 

 break through in the neighboring sea. In January, 1783, such 

 an irruption took place in the sea, eight geographical miles from 

 Cape Reikianes, several islands were raised, and great quantities 

 of pumice and light slags were floated on the coast. In June, 

 the whole island was shaken by earthquakes. The submarine 

 eruption discontinued, and at a distance of fifty geographical 

 miles, the grand eruption of Skaptar Jokul commenced. On 

 the 13th June, 1830, a similar submarine eruption was re- 

 peated. J 



The immense masses of lava ejected from a single volcano, 

 and the enormous extent in which volcanic actions are felt at 

 the same time, scarcely leave room to doubt that every active 

 volcano is in immediate communication with the whole melted 

 matter in the interior. In this manner alone can it be conceived, 

 how, for instance, the masses ejected at different times from 

 Vesuvius vastly exceed the whole balk of the mountain, >§> while 

 the latter seems upon the whole to undergo no diminution, for 



* See Om Tordbranden paa Island i Aaret 1783, ved Student Soemund Mag 

 nussen. Kort besUrivelse over den eye Vulkans, Ildsprudning i Vaster Skopte- 

 fells Syssel paa Island i Aaret 1783 of Magnus Stephen sen. Kiobenhavn 1785. 

 Sir G. Makenzie's Travels in Iceland. Ganlieb's Island, 1819, p. 64. Th. 

 Gliemann geogr. Beschreibung von Island, 1824, p. 107. Pennant le Nord de 

 Globe, t. i. 



t Barghaus Almanac for 1838, p. 75. 



t Journ. de Geologie, t. i. 



§ This was remarked even by the ancients ; and Seneca, Letter 79, after stating 

 the difficulty, solves it by remarking, that the fire of the volcano, " in ipso monte 

 non alimentum habet, sed viam."— Daubeny on Volcanos, p. 155. 



