Natural History of Volcanos and Earthquakes. 261 
Daring 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 
Blane.t Under almost the whole of Iceland, there is a voleanic 
furnace, which communicates by many apertures with the sur- 
e. The masses of melted matter, therefore, seek an outlet at 
Various points, and many places are mentioned, at which the lava 
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 
ape 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 
*tuption discontinued, and at a distance of fifty geographical 
mniles, the grand eruption of Skaptar Jokul commenced. On 
the 13th June, 1830, a similar submarine eruption was_ re- 
peated. + 
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, 
W, for instance, the masses ejected at different times from 
Suvius vastly exceed the whole bulk of the mountain,$ while 
the latter seems upon the whole to undergo no diminution, for 
ae ees east 
"See Om Tordbranden paa Island i Aaret 1733, ved Student Soemund Mag 
— Kort beskrivelse over den eye Vulkans, Ildsprudning | Vester Skopte- 
. »yssel paa Island i Aaret 1783 of Magnus Stephen sen. Kidébenhava 1785, 
9, p. 64. Th, 
qamene geogr. Beschreibung von Island, 1824, p. 107. Pennant Ie Nord de 
bi 
: Berghaus Almanac for 1838, p. 75. 
°urn. de Geologie, t. i. x : 
§ This was rie ey even by the ancients; and Seneca, Letter 79, after stating 
difficulty, solves it by remarking, that the fire of the volcano, ‘in ipso monte 
nn alimentum habet, sed viam.”—Daubeny on Volcanos, p. 155. 
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PO Se ee Sen eee 
