386 STRUCTURE, AND MODE OF ACTION 



highest, in what year the artist had taken the sketch from which the 

 picture was made. 



In the last eruption, in the night of the 23d to the 24th of Octo- 

 ber, twenty-four hours after the falling in of the great cone of scoriae 

 which has been mentioned, and when the small but numerous cur- 

 rents of lava had already flowed off, the fiery eruption of ashes and 

 rapilli commenced : ' it continued without intermission for twelve 

 days, but was greatest in the first four days. During this period, 

 the detonations in the interior of the volcano were so violent that 

 the mere concussion of the air (for no earthquake movement was 

 perceived) rent the ceilings of the rooms in the palace of Portici. 

 In the neighboring villages of Resina, Torre del Greco, Torre del 

 Annunziata, and Bosche Tre Case, a remarkable phenomenon was 

 witnessed. Throughout the whole of that part of the country the 

 air was so filled with ashes as to cause in the middle of the day pro- 

 found darkness, lasting for several hours : lanterns were carried in 

 the streets, as has so often been done at Quito during the eruptions 

 of Pichincha. The flight of the inhabitants had never been more 

 general : lava currents are regarded by those who dwell near Vesu- 

 vius with less dread than an e'ruptkm of ashes, a phenomenon which 

 had never been known to such a degree in modern times ; and the 

 obscure tradition of the manner in which the destruction of Hercu- 

 laneum, Pompeii, and Stabiae took place, filled the imaginations of 

 men with appalling images. 



The hot aqueous vapors which rose from the crater during the 

 eruption and spread themselves in the atmosphere, formed, in cool- 

 ing, a dense cloud, surrounding the column of fire and ashes, which 

 rose to a height of between nine and ten thousand feet. So sudden 

 a condensation of vapor, and even, as Gay-Lussac has shown, the 

 formation of the cloud itself, augmented the electric tension. Flashes 

 of forked lightning, issuing from the column of ashes, darted in 

 every direction ; and the rolling thunders were distinctly heard, and 

 distinguished from the sounds which proceeded from the interior of 

 the volcano. In no other eruption had the play of the electric forces 

 formed so striking a feature. 



On the morning of the 26th of October, a surprising rumor pre- 

 vailed, to the effect that a torrent of boiling water was gushing from 



