Oct. 1, 1868.] 



HABDWICKE'S SCIENCE-GOSSIP. 



219 



ground did not share the same agitation. But since 

 December, 1797, new communications appear to 

 have been opened in the interior of the globe. The 

 peninsula of Araya is now not merely subject to the 

 same agitations as the soil of Cumana, but the pro- 

 montory of mica-slate, previously free from' earth- 

 quakes, has become in its turn a central point of 

 commotion. The earth is sometimes strongly shaken 

 at the village of Maniquarez, when on the coast of 

 Cumana the inhabitants enjoy the most perfect tran- 

 quillity. The Gulf of Cariaco, nevertheless, is only 

 sixty or eighty fathoms deep. 



It has been thought, from observations made both 

 on the continent and in the islands, that the western 

 and southern coasts are most exposed to shocks. 

 This observation is connected with opinions which 

 geologists have long formed respecting the position 

 of the high chains of mountains, and the direction 

 of their steepest declivities ; but the existence of 

 the Cordillera of Caracas, and the frequency of the 

 oscillations on the eastern and northern coast of 

 Terra Eirma, in the Gulf of Paria, at Carupano, at 

 Cariaco, and at Cumana, renders the accuracy of that 

 opinion doubtful. 



In New Andalusia, as well as in Chile and Peru, 

 the shocks follow the course of the shore, and 

 extend but little inland. This circumstance, as 

 we shall soon find, indicates an intimate connection 

 between the causes which produce earthquakes and 

 volcanic eruptions. If the earth was most agitated 

 on the coasts, because they are the lowest part of 

 the land, why should not the oscillations be equally 

 strong and frequent on those vast savannahs or 

 prairies, which are scarcely eight or ten toises above 

 the level of the ocean ? 



The earthquakes of Cumana are connected with 

 those of the West India islands ; and it has even 

 been suspected that they have some connection with 

 the volcanic phenomena of the Cordilleras of the 

 Andes. On the 4th of February, 1797, the soil of 

 the province of Quito suffered such a destructive 

 commotion that near 40,000 natives perished. At 

 the same period the inhabitants of the eastern 

 Antilles were alarmed by shocks, which continued 

 during eight months, when the volcano of Guada- 

 loupe threw out pumicestones, ashes, and gusts of 

 sulphureous vapours. The eruption of the 27th of 

 September, during which very long continued sub- 

 terranean noises were heard, was followed on the 

 14th of December by the great earthquake of 

 Cumana. Another volcano of the West India 

 islands, that of St. Vincent, affords an example of 

 these extraordinary connections. This volcano had 

 not emitted flames since 1718, when they burst forth 

 anew in 1812. The total ruin of the city of Caracas 

 preceded this explosion thirty-five days, and violent 

 oscillations of the ground were felt both in the 

 islands and on the coasts of Terra Eirma. 

 It has long been remarked that the effects of 



great earthquakes extend much farther than the 

 phenomena arising from burning volcanoes. In 

 studying the physical revolutions of Italy, in care- 

 fully examining the series of the eruptions of 

 Vesuvius and Etna, we can scarcely recognize, not- 

 withstanding the proximity of these mountains, any 

 traces of a simultaneous action. It is, on the con- 

 trary, beyond a doubt that at the period of the last 

 and preceding destruction of Lisbon the sea was 

 violently agitated even as far as the New World, 

 for instance, at the island of Barbadoes, more than 

 twelve hundred leagues distant from the coast of 

 Portugal. 



Several facts tend to prove that the causes which 

 produce earthquakes have a near connection with 

 those which act in volcanic eruptions. The con- 

 nection of these causes was known to the ancients, 

 and it excited fresh attention at the period of the 

 discovery of America. The discovery of the New 

 World not only offered new productions to the 

 curiosity of man ; it also extended the then existing 

 stock of knowledge respecting physical geography, 

 the varieties of the human species, and the migra- 

 tions of nations. It is impossible to read the 

 narratives of early Spanish travellers, especially 

 that of the Jesuit Acosta, without perceiving the 

 influence which the aspect of a great continent, the 

 study of extraordinary appearances of nature, and 

 intercourse with men of different races must have 

 exercised on the progress of knowledge in Europe. 

 The germ of a great number of physical truths is 

 found in the works of the sixteenth century, and 

 that germ would have fructified, had it not been 

 crushed by fanaticism and superstition. We 

 learned at Pasto that the column of black and 

 thick smoke which, in 1797, issued for several 

 months from the volcano near that shore disap- 

 peared at the very hour when, sixty leagues to the 

 south, the towns of Biobainba, Hambato, and 

 Tacunga were destroyed by an enormous shock. 

 In the interior of a burning crater, near those 

 hillocks formed by ejections of scoriae and ashes, 

 the motion of the ground is felt several seconds 

 before each partial eruption takes place. We 

 observed this phenomenon at Vesuvius in 1S05, 

 while the mountain threw out incandescent scoriae ; 

 we were witnesses of it in 1802, on the brink of the 

 immense crater of Pichincha, from which, neverthe- 

 less, at that time, clouds of sulphureous acid vapours 

 only issued. 



Everything in earthquakes seems to indicate the 

 action of elastic fluids seeking an outlet to diffuse 

 themselves in the atmosphere. Often, on the coasts 

 of the Pacific, the action is almost instantaneously 

 communicated from Chile to the Gulf of Guayaquil, 

 a distance of six hundred leagues ; and, what is 

 very remarkable, the shocks appear to be the 

 stronger in proportion as the country is distant 

 from burning volcanoes. The granitic mountains of 



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