348 Senry Woodioard — On Volcanos. 



Heat may be retained in parts of lava streams for a period of 

 twenty years. 



From the crater of Galongoon, in Java, in 1822 (after an earth- 

 quake shock), was vomited out immense columns of boiling water, 

 mud, steam, brimstone, ashes, and lapilli, in such mass and with such 

 violence as to fall 40 miles distant. The valleys were all filled ; 

 24 square miles were covered to a depth of more than 100 feet (in 

 places) with hot blue mud, burying houses, villages, and people. 

 The second eruption followed (preceded by terrific rains), accom- 

 panied by hot water and mud, and great blocks of basalt were 

 thrown seven miles ! One side of the crater was rent away, new 

 hills and valleys were formed, and two rivers changed their courses. 

 In one night 2,000 persons were killed ; altogether the official return 

 shows 114 villages destroyed, and above 4,000 persons killed.'^ 



In January, 1803, all the snows were dissolved off Cotopaxi in 

 one night, causing vast deluges of mud to descend, with great de- 

 struction to the region around. 



The deluges caused by lake-craters probably exceed in magnitude 

 and destructiveness those of lava-streams. 



In 1797 a mud-debacle poured from Tunguragua, in Quito, filled 

 a valley 1000 feet wade to the depth of 600 feet. Many small fish 

 were observed enveloped in the mud. No doubt the fossil fishes 

 and insects found at Oeningen were brought down from an old crater- 

 lake by a Miocene volcano. Similar deposits, also of volcanic origin, 

 rich in fossil fishes, are found at Aix, in Provence. 



The volcano of Imbaburu, in 1691, vomited forth so many fishes 

 that it bred fever, from the stench caused by their decomposition, 

 and that of other animals destroyed by the debacle. 



The distance to which the sound of volcanic explosions is trans- 

 mitted, and the fine ashes scattered by the currents of the air, is 

 truly wonderful. " On the night of 30th April," writes Professor 

 Dove,^ " explosions like those of heavy artillery were heard at Bar- 

 badoes, so that the garrison at Port St. Anne remained all night 

 under arms. On May 1st, at daybreak, the eastern portion of the 

 horizon appeared clear, whilst the rest of the firmament was covered 

 by a black cloud, which soon extended to the East and quenched the 

 light there, and at length produced a darkness so dense that the 

 windows in the rooms could not be discerned. A shower of ashes 

 descended, under which the tree branches bent and broke. Whence 

 came these ashes ? From the direction of the wind we should infer 

 that they came from the Peak of the Azores ; they came, however, 

 from the volcano of Morne Garou, in St. Vincent, which lies about 

 100 miles West of Barbadoes. The ashes had been cast up with 

 such force as to enter into the current of the upper trade-wind. 



"A second example of the same kind occurred in January, 1835. 

 On 24th and 25th the sun was darkened in Jamaica by a shower of 

 fine ashes, which had been discharged from the mountain Coseguina, 

 800 miles distant. The people learned in this way that the explosions 



^ Van der Boon Mesch, in Lyell's " Principles of Geology," vol. ii., p. 66. 

 2 Dove, Prof. "Witterungs Verhaltnisse von Berlin, in Tyndall's " Heat as a Mode 

 of Motion," p. 166. 



