c 266 Notice of Active and Extinct Volcanos. 



for the falling in of its cone at one period appears to be balanced 

 by the accumulation of ashes at another. 



" The cities of Stabiae, Pompeii, and Herculaneum, which 

 were destroyed in the course of this eruption, appear to have 

 been overwhelmed, not by a stream of melted matter, but by a 

 shower of cinders and loose fragments ; * for the various utensils 

 and works of art that have been dug from thence nowhere exhi- 

 bit any signs of fire, and even the delicate texture of the Papyri 

 appears to have been affected only in proportion as it has subse- 

 quently been exposed to air and moisture. Thus in those at 

 Pompeii, which was covered by a mere uncemented congeries of 

 sand and stones, decomposition has proceeded so far that their 

 contents are illegible, whereas at Herculaneum, where they have 

 been preserved under a species of tuff, their characters often 

 admit of being decyphered. Now the formation of this latter 

 substance is explained on the supposition of a torrent of mud 

 having accompanied in this quarter the ejections of the volcano, 

 which favoring the agglutination of the loose materials, reduced 

 them to a state, which though less consistent than tuff generally 

 is, was capable of preventing in some degree the access of air 

 and humidity to the substances underneath. Sir W. Hamilton 

 notices a fact, which shews very conclusively both that the tuff 

 of Herculaneum was once in a pasty state, and that it owed its 

 softness not to heat but to moisture, the head of a statue that was 

 dug up, having left a cast in the tuff which had formed upon it, 

 without appearing to be itself in the least scorched." 



In the notice of Mr. Scrope's work the principal recorded 

 eruptions of Vesuvius have been already mentioned, and it 

 is not necessary to repeat the statement. During the late 

 century the volcano was very active — there being eighteen 

 eruptions in the course of one hundred years. 



" That of 1737, gave rise to a stream of lava, which pass- 

 ed through the town of Torre del Greco, and continued its 

 course until arrested by the sea, at which time its solid con- 

 tents were estimated at thirty three millions five hundred and 

 eighty seven thousand fifty eight cubic feet." 



In the formidable eruption of 1 794, the town of Torre del 

 Greco was again destroyed, and the current of lava advanced 

 into the sea three hundred and sixty two feet, with a front of 

 one thousand one hundred and twenty seven feet. 



The cubic contents of this current were estimated by Bries- 



* The stones that fell at Pompeii are said many of them to weigh eight pound, 

 the largest of Stahise only an ounce. 



