No. II. — Herculaneum, Pompeii, and Stahiae* 12t9 



zolana, and lapilli, we never find tufa ; * and to get over the 

 difficulty which the example of Herculaneum affords, he adopts 

 a theory with which I am not acquainted, though I have be- 

 fore heard of the work by Lippi to which he alludes, and 

 which asserts the apparent paradox, that Herculaneum was 

 not destroyed by an eruption of Vesuvius, by a peculiar dilu- 

 vium. I am, however, decidedly of opinion, that the pheno- 

 mena we have considered are not at variance with the theory 

 of submarine volcanos, and that there is no necessity for such 

 far-fetched and problematical explanations of the interment of 

 Herculaneum. 



The excavations of Pompeii and Stabij: demand less bX- 

 tention in a physical point of view than those at Herculaneum. 

 My remarks may be confined within a short compass. The 

 former was discovered in 1750, the latter about two years 

 sooner. A shower of true volcanic ashes was the cause of the 

 catastrophe ; and I need not repeat what I have already said 

 on this part of the subject. These ashes, it is to be remarked, 

 are essentially distinct from volcanic dust, which is nearly an 

 impalpable powder ; but the covering of Pompeii is composed 

 of real cinereous particles, vitrified, and harsh to the feel. The 

 lower strata approach in nature to white pumice, and the up- 

 per part is vegetable soil, in which vines grow. Even below 

 the buildings of Pompeii this vegetable mould is found, and 

 no less than three successive strata of black lava containing 

 leucites, which carry us back to the most remote antiquity. 

 The very houses of the town are a standing testimony to the 

 volcanic productions of primaeval times. The following are 

 reckoned among the building stones. 1. The old, dark, leu- 

 citic lava. % Reddish cellular lava, extremely porous. 3. 

 Gray and yellow volcanic tufa. 4 Calcareous tufa from the 

 river Sarno. -|- The depth of the shower of ashes varies con- 

 siderably. It is seldom, however, very great. There are 



• '^ Tra i prodotti dei moderni Vulcani che ardono nei Continent! veg- 

 gonsi bensi, scorie, cenere, pozzulaiie, lapilli ; tufa non mai." 



t Ferber's Travels j p. 152. I cannot help here remarking the extraor- 

 dinary want of information on the most important points, and the frequent 

 errors of this work, intended solely as a mineralogical tour through 

 Italy. 



VOL, X, NO. I. JAN. 1829. I 



