vertical wall seventy metres in height, and another slope, which extends to the bottom. In total, the mean depth of this imposing abyss will reach 250 m. to 300 m.
At the place, where the vertical wall begins and the first slope ends, there has been set up a sort of a windlass, below which an enormous beam slopes downward toward the abyss; by this beam, and lowered by a cord, the workmen who extract sulphur descend.
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