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Show 350 COMPOSl'l'ION OF 'rilE MASS ENVELOPING f k hich are thrown out near larue angular fragments. o roc ' d~ ~tance where small lapilli o ld b ntmu at a 1;:, ' • the vent, wou e wa 0 d' 1 with these exceptwns, no only wou ld b e £o u nd · Accor lm g Yt•h e form and d1. stn' b ut1· 0n . b e perfect t 1an . b identity can e mor of Monte Nuovo, as lmd open y of the matte.r at the basethe a earance of the beds super-the encroachmg sea, and PtP ·s covered with numerous · · 'I' hat c1 y I imposed on Pompen. l . t 1 beds of tuff and lapilli, for alternations of different 10rizobnd~ 'd d into very fine layers. th'n and su lVI e . the most part 1 ' • t' near the Amphitheatre, m I observed the followmg s~c Ion . b 18")8 -(descendmg senes). Novem er, "' ' Feet. I1lcl1e1. the erultion of 1822, containing 1. Black sparkling sand from t 1 I f augite and tourmaline minute regularly-formed crys a s 0 • • • 2 to a• from • ' ' , • 3 0 2. Vegeta~le mould uff full• of .,i;olitic ;tubule: in layers, from 3. Brown mcoherent t . r. , , , half an inch to 3 inches l.n ~hlckness • • • 4. Small scorim and white lapilh • . i·r lobules tl t ff with numerous plso l lC g 5. Brown car lY u ff . th 1 pilli divided into layers 6. Brown earthy tu w~ . a • • 7• Layer of whitish lap1lh • 8. Grey solid tuff •. . • 9• Pumice and white lapilli 1 6 0 3 0 9 4 0 0 1 0 3 0 3 10 4 • hese beds are vitrified and harsh to Many of the ashes m t . t b th fresh and farinaceous, have the touch. . Cryst~ls o~ leu~~~ ;e th of the bed of ashes above been found mtermixedr. d p ds twelve or fourteen . . bl but sel om excee . the houses 1s vana ~. . t f the Amphitheatre feet and it is said, that the hig~er parth :uh if this were the ' . d b the sur1ace; 0 b ' • always proJecte a ove r bl that the city should never case, it seems to be i.nexp Ica re 1750. It will be observe~, have been discovered till the yea f th brown half-consoh· in the above section, that two o e . . 1822 only caused a. coven.n g of a few innch eosf * The last great eruption,;\ 'mentioned by Mr. Forbes:-Ed. Jo~ .e it thick on Pompeii. Several le:29 ~r~ut he must have measured m s~t;h: ~;:ter, Science, No. xix., P· 131, J~. hcs 'were five feet thick at t~e top ~he size and had drifted. The dust an as . Torre del Annunziata. . us and decreased grallually to ten ;.nc?~\1:! very regularly in the same conhuuo wei!!ht of the ejected fragments umtmsof proiection was greater. o . t f om the cen re J stratum as the dts ance r . ·x , 130, Jan. 1829. t Forb es, Ed · Journ • of Sc1.1 No. XI ., P liERCULANEUM AND POMPEII, 351 dated tuffs are filled with small pisolitic globules. It is surprising that this circumstance is not alluded to in the animated controversy which the Royal Academy of Naples maintained with one of their members, Signor Lippi, as to the origin of the strata incumbent on Pompeii. The mode of aggregation of these globules has been fully explained by Mt·. Scrope, who saw them formed in great numbers, in 1822, by rain falling during the eruption on fine volcanic sand, and sometimes, also, beheld them produced like hail in the air, by the mutual attraction of the minutest particles of fine damp sand. Their occurrence, therefore, agrees remarkably well with the account of heavy rain, and showers of sand and ashes, recorded in history, and is opposed to the theory of an a1lu4 vion brought from a distance by a flood of water. Lippi entitled his work" Fu il fuoco o l' acqua che sotterro Pompei ed Ercolano ?">K' and he contended that neither were the two cities destroyed in the year 79, nor by a volcanic eruption, but purely by the agency of water charged with transported matter. His Letters, wherein he endeavoured to dispense, as far as possible, with igneous agency, even at the foot of the volcano, were dedicated with great propriety to Werner, and afford an amusing illustration of the polemic style in which geological writers of that day indulged themselves. Hi_s arguments were partly of an historical nature, derived from the silence of con~ temporary historians, respecting the fate of the cities which, as we have already stated, is most 1·emarkable; and were partly drawn from physical proofs. He pointed out with great clearness the resemblance of the tufaceous matter in the vaults and cellars at Herculaneum and Pompeii to aqueous alluvions, and its distinctness from ejections which had fallen through the air. Nothing, he observed, but moist~ pasty matter could have received the impression of a woman's breast, which was found in a vault at Pompeii, or have given the cast of a statue discovered in the theatre at Herculaneum. It was objected to him, that the heat of the tuff in Herculaneum and Pompeii was proved by the carbonization of the timber, corn, papyrusrolls, and other vegetable substances there discovered: but Lippi replied with truth, that the papyl'i would have been * .N apoli1 1816, |