The crater can alone be reached by descending down three chasms. Its sides are absolutely precipitous within, and are most elevated toward the north. Its form is elliptical; its circumference about twelve hundred feet; and its depth according to Cordier, one hundred and ten feet. Humboldt, however, estimates it at not more than from forty to sixty feet. The sides are, agreeably to the former of these observers, formed of an earth of snowy whiteness, resulting from the decomposition of the blackest and hardest vitreous porphyritic lava. All the rest is solid, and the lowest part occupied by blocks, which have fallen down from the sides. These solid parts are covered with shining crystals of sulphur, of a rhomboidal and octahedral figure, some of which are nearly an inch high, and are, perhaps, the finest specimens of native volcanic sulphur yet known. Vapors issue in abundance from among these blocks, and from an infinity of fissures which preserve a very intense heat. These vapors consist solely of sulphur and water, perfectly insipid. Beside the incrustations of sulphur, opal, in thin plates, is formed with great celerity. Humboldt regards the peak of Teneriffe as an enormous basaltic mountain, resting upon a dense secondary calcareous stone. Various travelers have asserted, that the cold is intensely keen on the summit of the peak; that respiration is difficult; and that, particularly, spirituous liquors lose all their strength; which latter circumstance they ascribe to the spirit being more or less exposed to the sulphureous fumes exhaled from the crater. Cordier, and several other accurate observers, declare, however, that neither the smell nor the strength of liquids appeared, at this elevation, to be in the least degree impaired; and that volatile alkali, ether, and spirit of wine, possessed their usual pungency. They add, that the cold is very supportable; and that neither the aqueous sulphureous vapors, nor the rarity of the air, render breathing difficult. We extract the following interesting particulars from Humboldt’s account of his visit to Teneriffe. “Toward three in the morning, by the sombrous light of a few fir torches, we began our expedition for the summit of the Piton. We scaled the volcano on the north-east, where the declivities are extremely steep; and came, after two hours’ toil, to a small plain, which on account of its isolated situation, bears the name of Alta Vista. It is the station also of the Neveros, those natives whose occupation it is to collect ice and snow, which they sell in the neighboring towns. Their mules, better practiced in climbing mountains than those hired by travelers, reach Alta Vista, and the Neveros are obliged to transport the snow to this place on their backs. Above this point the Malpays begins; a term by which is designated here, as well as in Mexico, Peru, and every other country subject to volcanoes, a ground destitute of vegetable mold, and covered with fragments of lavas.