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Natural History of Volcanos and Earthquakes. AT 
have at different periods ravaged Smyrna,* Messina,+ Kings- 
town in Jamaica 1792, the county of Pignerol 1808,f Cala- 
bria,|| Talcahuano in Chili,§ &c., have always had a greater 
effect on diluvium and alluvium, than on rocks. Houses, for in- 
stance, built on sandy ground, were demolished, while those 
which stood on rocks were but little damaged. The shocks 
therefore act less violently and destructively on solid and rocky 
ground than on loose soil, which is unable to resist, and propa- 
gates the shock irregularly. In Calabria, where the loose soil 
occurred lying on granite on the declivity of the hills, the latter 
threw off the former, which glided down. Lastly, there are also 
instances of shocks extending irregularly in rocks. 
Many instances present themselves of earthquakes, which in 
extending longitudinally, follow the direction of the rocks. This 
is the case, according to Palassou,** in the Pyrenees. _Remarka- 
ble instances are presented in the phenomena of the 28th Dec. 
1779; the 10th July 1784; the 8th July 1791; the 22d May 
18 ¢. The regions situated more to the south, are, how- 
ever, more affected than the chain itselft+ Earthquakes in” 
South America seem also to follow the direction of the mountains. 
Thus, that at Caraccas (1812) followed the direction of the lit- 
toral Cordilleras from E. N. E. to W. S. W.tt That of Cumana 
797, presented an instance of the same fact. The predominant 
direction of the frequent earthquakes on the coasts of Chih and 
Peru, is also that of the large chain of the Andes, which is par- 
allel to the coast.|||| \ All the older reports likewise state, that in 
these countries their direction is from S. to N., or vice versa ; and 
rs. Graham remarked, that she felt, during the violent earth- 
quake in Chili 1822, as if the whole ground from north to south 
potty bE 
tranquillity was restored, a whirlpool was observed in the sea, as if the waters 
Were being swallowed up in an immense gulf. The temperature of the sea in the 
* Hist. de I’ Acad. des Sciences, an. 1688. Buffon, Hist. Nat. t. i, p. 515. 
' Spallanzani, Voyage, t. iv, p. 138. + Journ. de Phys. t. Ixvii, p. 238. 
I Oryktologische Bemerkungen ber Calabrien &c., 17 
§ Nautical Magazine, Nos. 49 and 51, March and June 1836. 
T Berghaus’ Almanack ftir das Jahr 1837, p. 72. 
ém. pour servir 4 l’Hist. Nat. des Pyren., p. 260. 
1 Ibid p. 916, tt Von Humboldt, Rel. Hist. t. v. 
Ill That at Cumana followed the direction from N. to 8., which is extremely sin- 
gular, l. cit, t. iv, p. 16. 
