Curiosities of Science. 1 1 9 



THE SNOW-CAPPED VOLCANO. 



It is but rarely that the elastic forces at work within the 

 interior of our globe have succeeded in breaking through the 

 spiral domes which, resplendent in the brightness of eternal 

 snow, crown the summits of the Cordilleras ; and even where 

 these subterranean forces have opened a permanent communi- 

 cation with the atmosphere, through circular craters or long 

 fissures, they rarely send forth currents of lava, but merely 

 eject ignited scoriae, steam, sulphuretted hydrogen gas, and 

 jets of carbonic acid. Humboldt's Cosmos, vol. i. 



TRAVELS OF VOLCANIC DUST. 



On the 2d of September 1845, a quantity of Volcanic Dust 

 fell in the Orkney Islands, which was supposed to have origin- 

 ated in an eruption of Hecla, in Iceland. It was subsequently 

 ascertained that an eruption of that volcano took place on the 

 morning of the above day (September 2), so as to leave no 

 doubt of the accuracy of the conclusion. The dust had thus 

 travelled about 600 miles ! 



GEEAT ERUPTIONS OF VESUVIUS. 



In the great eruption of Vesuvius, in August 1779, which 

 Sir William Hamilton witnessed from his villa at Pausilippo 

 in the bay of Naples, the volcano sent up white sulphureous 

 smoke resembling bales of cotton, exceeding the height and 

 size of the mountain itself at least four times ; and in the midst 

 of this vast pile of smoke, stones, scoriae, and ashes were thrown 

 up not less than 2000 feet. Next day a fountain of fire shot 

 up with such height and brilliancy that the smallest objects 

 could be clearly distinguished at any place within six miles or 

 more of Vesuvius. But on the following day a more stupen- 

 dous column of fire rose three times the height of Vesuvius 

 (3700 feet), or more than two miles high. Among the huge 

 fragments of lava thrown out during this eruption was a block 

 108 feet in circumference and 17 feet high, another block 

 66 feet in circumference and 19 feet high, and another 16 feet 

 high and 92 feet in circumference, besides thousands of smaller 

 fragments. Sir William Hamilton suggests that from a scene 

 of the above kind the ancient poets took their ideas of the 

 giants waging war with Jupiter. 



The eruption of June 1794, which destroyed the greater 

 part of the town of Torre del Greco, was, however, the most 

 violent that has been recorded after the two great eruptions of 

 79 and 1631. 



EARTH-WAVES. 



The waves of an earthquake have been represented in their 



