and rises from a table-land, the elevation of which is more than one thousand five hundred toises above the valley of the Magdalena. In all the colossal mountains of Quito, of the province of Los Pastos, and of Popayan, crevices and valleys without number are interposed. It cannot be admitted, under these circumstances, that the noise could be transmitted through the air, or by the superior surface of the Globe, and that it came from that point, where the cone and crater of Cotopaxi are placed. It appears probable, that the higher part of the kingdom of Quito and the neighbouring Cordilleras, far from being a group of distinct volcanoes, constitute a single swollen mass, an enormous volcanic wall, stretching from South to North, and the crest of which exhibits a surface of more than six hundred square leagues. Cotopaxi, Tunguragua, Antisana, and Pichincha, are placed on this same vault, on this raised ground. They are differently named, although they are only different summits of the same volcanic mass. The fire issues sometimes from one, sometimes from another of these summits. The obstructed craters appear to us to be extinguished volcanoes; but we may presume, that, while Cotopaxi or Tunguragua have only one or two eruptions in the course of a century, the fire is not less continually active under the town of Quito, under Pichincha and Imbaburu.

The

Advancing toward the North, we find, between the volcano of Cotopaxi and the town of Honda, two other systems of volcanic mountains, those of Los Pastos and of Popayan. The connection of these systems was manifested in the Andes in an incontestible manner by a phenomenon, which I have already had occasion to notice, in speaking of the last destruction of Cumana. Since the month of November, 1796, a thick column of smoke had issued from the volcano of Pasto, West of the town of that name, and near the valley of rio Guaytara. mouths of the volcano are lateral, and placed on its western declivity, yet during three successive months the column rose so much higher than the ridge of the mountain, that it was constantly visible to the inhabitants of the town of Pasto. They related to us their astonishment, when, on the 4th of February, 1797, they observed the smoke disappear in an instant, without feeling any shock whatever. At that very moment, sixty-five leagues to the South, between Chimborazo, Tunguragua, and the Altar (CapacUrcu), the town of Riobamba was overthrown by the most dreadful earthquake, of which tradition has transmitted the history. Is it possible to doubt from this coincidence of phenomena, that the vapours, issuing from the small apertures or ventanillas of the volcano of Pasto, had an influence on the pressure of those elastic

fluids, which shook the ground of the kingdom of Quito, and destroyed in a few minutes thirty or forty thousand inhabitants?

In order to explain these great effects of volcanic reactions, and to prove, that the group or system of the volcanoes of the West India Islands may sometimes shake the continent, it was necessary to cite the Cordillera of the Andes. Geological reasoning can be supported only on the analogy of facts that are recent, and consequently well authenticated: and in what other region of the Globe could we find greater and at the same time more varied volcanic phenomena, than in that double chain of mountains heaved up by fire? in that land, where Nature has covered every summit and every valley with her marvels? If we consider a burning crater only as an isolated phenomenon, if we satisfy ourselves with examining the mass of stony substances which it has thrown up, the volcanic action at the surface of the Globe will appear neither very powerful, nor very extensive. But the image of this action swells in the mind, when we study the relations that link together volcanoes of the same group; for instance those of Naples and Sicily, of the Canary islands *, of the Azores, of the Caribbee

I have already related, vol. i, p. 249, how the whole group of the Canary islands are placed, as we may say, on one and the same submarine volcano; the fire of which,

islands of Mexico, of Guatimala, and of the table-land of Quito; when we examine either the reactions of these different systems of volcanoes on one another, or the distance to which, by subterranean communications, they at the same moment shake the Earth.

The study of volcanoes presents two very distinct branches; the object of one, simply mineralogical, is the examination of the stony strata, altered or produced by the action of fire; from the formation of the trachytes or trap porphyries, of basalts, phonolites, and dole

since the sixteenth century, has made it's appearance alternately in Palma, Teneriffe, and Lancerota. Auvergne presents us with a whole system of volcanoes, the action of which has ceased; but in the middle of a system of active volcanoes, for instance, in that of Quito, we must not consider as an extinguished volcano a mountain, the crater of which is obstructed, and through which the subterraneous fire has not issued for ages. Etna, the Eolian isles, Vesuvius, and Epomeo; the peak of Teyde, Palma, and Lancerota; St. Michael, la Caldiera de Fayal, and Pico; St. Vincent, St. Lucia, and Guadaloupe; Orizava, Popocatepec, Jorullo, and la Colima; Bombacho, the volcano of Granada, Telica, Momotombo, Isalco, and the volcano of Guatimala; Cotopaxi, Tunguragua, Pichincha, Antisana, and Sangay, belong to the same system of burning volcanoes; they are generally ranged in rows, as if they had issued from a crevice, or vein not filled up; and, what is very remarkable, their position is in some parts in the general direction of the Cordilleras, and in others in a contrary direction. (Essai politique sur le Mexique, tom. 1, p. 253.)

rites, to the most recent lavas; the other, less accessible and more neglected, comprehends the physical relations which link volcanoes together, the influence of one volcanic system on another, the connection that manifests itself between the action of burning mountains andthe commotions which shake the earth at great distances, and during a long time, in the same direction. This study cannot make any progress, till the various epochas of simultaneous action, the direction, the extent, and the force of the commotions, are carefully noted; as well as their progressive advance toward regions, which they had not yet reached*; and that coincidence between distant volcanic eruptions and those subterranean noises, which, on account of their force, the inhabitants of the Andes denominate in a very expressive manner subterraneous thunders, or roarings. All these objects are comprehended in the domain of the history of nature, a science which has not even' preserved it's name, and the origin of which, like that of all other histories, begins with times which appear to us fabulous, and catastrophes, of which our imagination cannot embrace the violence and magnitude.

The study of the history of nature has been long confined to that of the ancient documents

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