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 Llanos of Cumana, of New Barcelona, of Calabozo, of Apure, and of Meta.)

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 Guadaloupe threw out pumice-stones, ashes, and gusts of sulphureous vapours. The eruption of the 27th of September, during which very long-continued subterranean 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 Firma.

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 carefully examining the series of the eruptions of Vesuvius and Etna, we can scarcely recognise, notwithstanding the proximity of these mountains, any traces of a simultaneous action. It is on the contrary 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 Barbados, more than twelve hundred leagues distant from the coasts of Portugal.

(* Destruction of Lisbon: The 1st of November, 1755, and 31st of March, 1761. During the first of these earthquakes, the sea inundated, in Europe, the coasts of Sweden, England, and Spain; in America, the islands of Antigua, Barbados, and Martinique. At Barbados, where the ordinary tides rise only from twenty-four to twenty-eight inches, the water rose twenty feet in Carlisle Bay. It became at the same time as black as ink; being, without doubt, mixed with the petroleum, or asphaltum, which abounds at the bottom of the sea, as well on the coasts of the gulf of Cariaco, as near the island of Trinidad. In the West Indies, and in several lakes of Switzerland, this extraordinary motion of the waters was observed six hours after the first shock that was felt at Lisbon - Philosophical Transactions volume 49 pages 403, 410, 544, 668; ibid. volume 53 page 424. At Cadiz a mountain of water sixty feet high was seen eight miles distant at sea. This mass threw itself impetuously on the coasts, and beat down a great number of houses; like the wave eighty-four feet high, which on the 9th of June, 1586, at the time of the great earthquake of Lima, covered the port of Callao. - Acosta Hist. Natural de las Indias edition de 1591 page 123. In North America, on Lake Ontario, violent agitations of the water were observed from the month of October 1755. These phenomena are proofs of subterraneous communications at enormous distances. On comparing the periods of the great catastrophes of Lima and Guatimala, which generally succeed each other at long intervals, it has sometimes been thought, that the effect of an action slowly propagating along the Cordilleras, sometimes from north to south, at other times from south to north, may be perceived. - Cosmo Bueno Descripcion del Peru ed. de Lima page 67. Four of these remarkable catastrophes, with their dates, may be here enumerated.)

TABLE OF FOUR CATASTROPHES:

COLUMN 1 : MEXICO. (Latitude 13 degrees 32 minutes north.)

COLUMN 2 : PERU. (Latitude 12 degrees 2 minutes south.)

30th of November, 1577 : 17th of June, 1578.

4th of March, 1679 : 17th of June, 1678.

12th of February, 1689 : 10th of October, 1688.

27th of September, 1717 : 8th of February, 1716.

When the shocks are not simultaneous, or do not follow each other at short intervals, great doubts may be entertained with respect to the supposed communication of the movement.)

Several facts tend to prove that the causes which produce earthquakes have a near connection with those which act in volcanic eruptions. The connection 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 migrations 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, disappeared at the very hour, when, sixty leagues to the south, the towns of Riobamba, 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.

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