206 
POPULAE SCIENCE EEYIEW. 
streams were strewed with dead fish. This great eruption of 
Coseguina was accompanied by an earthquake which was felt 
over more than one thousand miles, the volcano having been 
dormant for twenty-six years. 
“ Moya/* or volcanic mud, which is composed of ashes and 
liquefied snow, descended, in 1797, from Tunguaragua, one of 
the Quito volcanos, and filled valleys six hundred feet deep, a 
thousand feet wide, and many miles in length, with a pulpy 
material, which dammed up rivers and caused lakes. 
The eruption of Skaptar Jokul, in Iceland, in 1783, destroyed 
no less than twenty villages, and caused the death of no less 
than nine thousand human beings out of a population which 
did not exceed fifty thousand, together with an immense 
number of cattle. Professor Bischoff has calculated that the 
mass of lava brought up from the subterranean regions by this 
single eruption surpassed in magnitude the bulk of Mont 
Blanc. At all events, there were erupted two enormous 
streams of lava, which flowed in nearly opposite directions, one 
of which was fifty miles long, and from twelve to fifteen miles 
in breadth, and the other forty miles in length by seven in 
width. The elastic forces that' eject these vast masses of 
volcanic materials from volcanic vents must be very great. 
The crater of Cotopaxi is more than three miles and a half 
above the sea, yet it has been known to eject a mass containing 
more than a hundred solid yards of rock to a distance of nine 
miles ; and it has been calculated that a column of lava one 
foot square, raised to the height of Cotopaxi, would weigh 
more than seven hundred and fifty tons. 
We have also evidence that volcanic eruptions into the sea, 
through fissures in the sea-bed, are by no means uncommon, 
though we have little opportunity of judging of their effects. 
Islands have been raised by volcanic elevation within the 
historical period, such as the island in the Aleutian group, 
described by Langsdorff, 3,000 feet high, and which was 
elevated in 1793. In the same year an island rose in the 
Azores; it was about a mile in circumference, and about 
300 feet above the level of the sea. It was composed of 
volcanic ashes and other light materials, and was soon washed 
away by the sea. Santarino, White Island, Hew Burnt 
Island, and several other islets in the Grecian Archipelago, 
are all due to submarine volcanic agency, and their elevation 
above the waters is recorded in authentic history. There are 
also numerous instances on record where the commanders of 
vessels have noted submarine eruptions, as evidenced by the 
escape of gases, and the destruction of marine animals. 
The intimate manner in which great earthquake shocks are 
connected with volcanic phenomena, makes the subject of any 
