NATURAL HISTORY. 



^97 



the 14th of December by the great 

 earthquake of Cutnana. Another 

 volcano of the West India Islands, 

 thatof St. Vincent's, has latelj given 

 a fresh instance of these extraordi- 

 nary connections. This volcano 

 had not emitted flames since 1718, 

 when they burst forth anew, in 1812. 

 The total ruin of the city of Cara- 

 cas preceded this explosion thirty- 

 five days, and violent oscillations 

 of the ground were felt, both iu 

 the islands, and on the coasts of 

 Terra Firma. 



It has long been remarked, that 

 the effects of great earthquakes ex- 

 tend much farther than the phse- 

 nomena arising from burning vol- 

 canoes. In studying the physical 

 revolutions of Italy, carefully exa- 

 mining the series of the eruptions 

 of Vesuvius and Etna, we can 

 scarcely recognize, notwithstand- 

 ing the proximity of these moun- 

 tains, any traces of a simultaneous 

 action. It is on the contrary doubt- 

 less, that at the period of the last 

 and preceding destruction of Lis- 

 bon, the sea was violently agitated 

 even as far as the New World, for 

 instance, at the island of Barba- 

 does, more than twelve hundred 

 leagues distant from the coasts of 

 Portugal. 



Several facts tend to prove, that 

 the causes which produce earth- 

 quakes have a near connection with 

 those that act in volcanic erup- 

 tions. We learn at Pasto, that 

 the column of black and thick 

 smoke, which, in 1797, issued for 

 several months from the volcano 

 near this shore, disappeared at the 

 very hour, when, sixty leagues to 

 the south, the towns of Riobamba, 

 Hambato, and Tacunga were over- 

 turned by an enormous shock. — 

 When, in the interior of a burn- 



VoL. LVI. 



ing crater, we are seated neir 

 those hillocks formed by ejections 

 of scoriae and ashes, we feel tlie 

 motion of the ground several se- 

 conds before each partial eruption 

 takes place. We observed this 

 phaenomenon at Vesuvius in 1805, 

 while the mountain threw out sco- 

 riae at a white heat ; we were wit- 

 nesses of it in 1812, on the brink 

 of the immense crater of Pichin- 

 cha, from which nevertheless at 

 that time clouds of sulphureous 

 acid vapours only issued. 



Every thing in earthquakes 

 seems to indicate the action of elas- 

 tic fluids seeking an outlet to spread 

 themselves in the atmosphere.— 

 Often, on the coasts of the South 

 Sea, the action is almost instanta- 

 neously communicated from Chili 

 to the gulphof Guayaquil, a distance 

 of six hundred leagues ; and, what 

 is very remarkable, the shocks ap- 

 pear to be so much the stronger, 

 as the country is more distant from 

 burning volcanoes. The granitic 

 mountains of Calabria, covered 

 with very recent breccia, the calca- 

 reous chain of the Apennines, the 

 country of Pigoerol, the coasts of 

 Portugal and Greece, those of 

 Peru and Terra Firma, afford strik- 

 ing proofs of this assertion. The 

 globe, it may be said, is agitated 

 with greater force, in proportion as 

 the surface has a smaller number 

 of funnels communicating with the 

 caverns of the interior. At Na- 

 ples and at Messina, at the foot of 

 Cotopaxiand of Tunguragua,earth- 

 quakes are dreaded only when va- 

 pours and flames do not issue from 

 the crater. In the kingdom of 

 Quito, the great catastrophe of 

 Riobamba, which we have before 

 mentioned, has led several well- 

 informed persons to think, that 



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