In the bottom of the crater are four fumaroles, whence vapors escape, which in issuing produce slight hissing sounds. Abundant deposits of sulphur exist near these. Besides the fumaroles mentioned, there are seven points at the borders of the crater, where gases escape, though in less abundance; six of these points lie to the east of the major diameter, and the seventh on the opposite side. All are inaccessible.
The interior of the crater is formed by sheets, which form a regular wall with vertical sides. In some places these layers are profoundly shattered and there various species of rocks, of notably different natures are seen; first, below, are sheets of trachyte, very compact and rich in crystals of striated feldspar and partly decomposed amphibole; above these more or less regular trachytic layers are beds of well-characterized basalt—also very compact and rich in peridote; lastly, above these layers are porous scoriæ, of dark purple color, which indicates the presence of a considerable quantity of iron oxide. These scoriæ must have originated from the fusion of the porphyritic rocks.
Every little while, at the summit, rage violent storms of snow, which falls in thick sheets; at such times the atmospheric clouds do not permit objects to be seen at a metre’s distance and the temperature falls to 20° and 22° below 0 C.
The exploitation of the sulphur is insignificant since only some forty-eight or fifty tons are taken out, in a year; this sulphur is distilled at the ranch of Tlamacas; it is sold in Mexico and Puebla at the same price as that of Sicily—that of Popocatepetl being superior in quality. The snow, too, on the side of Ozumba, is exploited, but this exploitation is on the smallest scale.
Various expeditions have been organized for the ascent of Popocatepetl, some scientific in nature, others for amusement. The first was made in 1519 by Diego de Ordaz, one of the soldiers of Cortes; others followed. In our own day, such expeditions are frequent and their results happily verify each other.
Ixtaccihuatl,—“white woman”—connected to Popocatepetl by a ridge of graceful outline, rises to 5,288 m. altitude above sea-level. Down the slopes of this mountain, several torrents, derived from the melting snows, pour and form cascades and falls up to forty-five metres in height. These same slopes, covered by a sheet of astonishingly rich and luxuriant vegetation are gashed by deep crevices, in which are enormous masses of porphyritic and basaltic rocks. Conifers form dense forests up to 3,000 m. altitude; from there the vigor of arborescent vegetation diminishes and at 4,000 m. it completely ceases; from that point on there are only stretches of brambles, which completely disappear at about 4,200 m.; then follow the sands, and, lastly, the perpetual snows, which begin at 4,300 m.
The crest, which is very grand and beautiful, resembles in the arrangement of its rock masses, the form of a woman’s body, stretched at length upon its back, and covered by a white winding sheet. From this, the name of white woman,—izta, white; cihuatl, woman—with which this lovely mountain was baptized by the dreamy imagination of the Aztecs.
THE CAVERN OF CACAHUAMILPA.
In the limestone mountains of Cacahuamilpa, thirty kilometres north from Tasco, in a ravine, lies the village of the same name, near which is situated the famous cavern, one of the most beautiful in the world, commonly designated by the name of the gruta de Cacahuamilpa (grotto of Cacahuamilpa).... Dominating the eminence formed in the cordillera running eastward and which has already been mentioned, is perceived the great mouth of the cavern, with the green festoons of foliage which adorn it and some stalactitic formations which seem to announce the marvels of the interior. Access to this entrance is gained by a short and narrow path.
The mouth measures five metres in its greatest height and thirty-six metres from side to side; after it has been traversed, there begins a plane sloping toward the interior; the soil is sandy; shortly one arrives at the first gallery, which is lighted by the sunlight.