432 DOMAIN XII. VOLCANIC, 



each other ; which beds are distinguishable by 

 their colour, and in many places project from 

 the mountain. They are almost all disposed 

 horizontally, and their position is not dissimilar 

 to the stratifications so frequently met with in 

 calcareous mountains. Each bed of pumice 

 does not form a distinct whole, which might 

 lead us to suppose that they had flowed at dif- 

 ferent intervals, and every current produced a 

 bed or stratum ; but it consists of an aggregate 

 of balls of pumice united together, but without 

 adhesion. It is hence evident that the pumices 

 were thrown out by the volcano in a state of 

 fusion, and took a globose form in the air, which 

 they preserved at the time of their sudden con- 

 gelation. We find many such eruptions of pu- 

 mices in the Phlegrean Fields ; as, for example, 

 that which overwhelmed and buried the unfor- 

 tunate town of Pompeii. The excavations which 

 have been made to exhibit to view some parts of 

 that city, manifestly show, that repeated ejec- 

 tions of small pumices in immense quantities 

 from Vesuvius, have covered it with vast accu- 

 mulations of that substance, disposed in different 

 beds or strata, 



" A great quantity of these Liparese pumices, 

 of a globular form, are first met with on the 

 shore near Campo Bianco; but as I doubted 



