1823.] M. Humboldt on Vokajioes, ^ 129 



but numerous currents of lava had already flowed, the fiery 

 eruption of ashes and rapilli began. It continued uninterrupt- 

 edly for twelve days, but was most violent during the first four. 

 During this time the detonations in the interior of the volcano 

 were so violent, that the mere concussion of the air (no earth- 

 quake had been observed) caused the roofs to burst in the palace 

 of Portici^ In the surrounding villages of Resina, Torre del 

 Greco, Torre del Annonciata, and Bosche tre Case, an interest- 

 ing phoenomenon was observed ; the atmosphere was so thickly 

 filled with ashes, that the most intense darkness overspread the 

 whole country for several hours in the middle of the day. The 

 people walked in the streets with lanterns, as is often done at 

 Quito when Pichincha is in eruption. The flight of the inhabi- 

 tants was never more general ; currents of lava were less feared 

 than a fall of ashes, a phenomenon which was unknown there 

 with such violence, and in consequence of the relations respect- 

 ing the destruction of Herculaneum, Pompeii, and Stabia?, filled 

 the minds of the people with frightful images. 



The hot steam which rose from the crater during the eruption 

 and passed into the atmosphere, formed on cooling a thick mass 

 of clouds, around the column of ashes and fire, 9000 feet in 

 height. This sudden condensation of steam, and, as Gay- 

 Lussac has shown, the very formation of the clouds, increases 

 the electric tension. Lightnings burst forth in all directions 

 from the column of ashes, and the rolling thunder might clearly 

 be distinguished from the interior noise of the volcano. At no 

 former eruption had the play of electric charges been so sur- 

 prising. 



On the morning of the 26th of October, a singular account 

 was circulated, that a current of boiling water had issued from 

 the crater, and rushed down from the cone of ashes. Monticelh, 

 the zealous and learned observer of the volcano, soon discerned 

 that the rumour had been occasioned by an optical deception. 

 The supposed current of water was nothing but a dry mass of 

 ashes, which flowed down, like quicksand, from a fissure in the 

 superior edge of the crater. A drought, which had completely 

 desolated the fields, preceded the eruption, but the volcanic 

 thunderstorm occasioned, towards its termination, a very heavy 

 and continued rain. Such a phenomenon characterizes the 

 conclusion of an eruption in every zone. On account of the cone 

 of ashes being generally covered wath clouds during this time, 

 and likewise because the torrents of rain are heaviest in its 

 neighbourhood, currents of mud flow down on all sides. The 

 affi'ighted peasant considers it to be water which has risen from 

 the interior of the crater, and the deceived geognost conceives 

 that he recognizes in it either sea-water, or mud-like volcanic 

 productions, which are called eruptions boueiisesj or, as the old 

 French systematic writers termed them, products of a fiery- 

 aqueous liq^uefaction. 



New Series, vol. vi, ^. 



':.■■■ m^\ - 



