The Outlines Of The Mountains Of Lancerota Appeared Stronger:

The humidity, increasing the transparency of the air, seemed at the same time to have brought the objects nearer our view.

This phenomenon is well known to all who have made hygrometrical observations in places whence the chain of the Higher Alps or of the Andes is seen. We passed through the channel which divides the isle of Alegranza from Montana Clara, taking soundings the whole way; and we examined the archipelago of small islands situated northward of Lancerota. In the midst of this archipelago, which is seldom visited by vessels bound for Teneriffe, we were singularly struck with the configuration of the coasts. We thought ourselves transported to the Euganean mountains in the Vicentin, or the banks of the Rhine near Bonn. The form of organized beings varies according to the climate, and it is that extreme variety which renders the study of the geography of plants and animals so attractive; but rocks, more ancient perhaps than the causes which have produced the difference of the climate on the globe, are the same in both hemispheres. The porphyries containing vitreous feldspar and hornblende, the phonolite, the greenstone, the amygdaloids, and the basalt, have forms almost as invariable as simple crystallized substances. In the Canary Islands, and in the mountains of Auvergne, in the Mittelgebirge in Bohemia, in Mexico, and on the banks of the Ganges, the formation of trap is indicated by a symmetrical disposition of the mountains, by truncated cones, sometimes insulated, sometimes grouped, and by elevated plains, both extremities of which are crowned by a conical rising.

The whole western part of Lancerota, of which we had a near view, bears the appearance of a country recently convulsed by volcanic eruptions. Everything is black, parched, and stripped of vegetable mould. We distinguished, with our glasses, stratified basalt in thin and steeply-sloping strata. Several hills resembled the Monte Novo, near Naples, or those hillocks of scoria and ashes which the opening earth threw up in a single night at the foot of the volcano of Jorullo, in Mexico. In fact, the abbe Viera relates, that in 1730, more than half the island changed its appearance. The great volcano, which we have just mentioned, and which the inhabitants call the volcano of Temanfaya, spread desolation over a most fertile and highly cultivated region: nine villages were entirely destroyed by the lavas. This catastrophe had been preceded by a tremendous earthquake, and for several years shocks equally violent were felt. This last phenomenon is so much the more singular, as it seldom happens after an eruption, when the elastic vapours have found vent by the crater, after the ejection of the melted matter. The summit of the great volcano is a rounded hill, but not entirely conic. From the angles of altitude which I took at different distances, its absolute elevation did not appear to exceed three hundred toises. The neighbouring hills, and those of Alegranza and Isla Clara, were scarcely above one hundred or one hundred and twenty toises.

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