The
openings of these cones of eruption, which rise from the bottom of the
crater, must not, as is too often done, be confounded with the crater which
incloses them. If this be inaccessible from extreme depth and from the
perpendicular descent, as in the case of the volcano of Rucu Pichincha,
which is 15,920 feet in height, the traveler may look from the edge on the
summit of the mountains which rise in the sulphurous atmosphere of the
valley at his feet; and I have never beheld a grander or more remarkable
picture than that presented by this volcano. In the interval between two
eruptions, a crater may either present no luminous appearance, showing
merely open fissures and ascending vapors, or the scarcely heated soil may
be covered by eminences of scoriae, that admit of being approached without
danger, and thus present to the geologist the spectacle of the eruption of
burning and fused masses, which fall back on the ledge of the cone of
scoriae, and whose appearance is regularly announced by small wholly local
earthquakes. Lava sometimes streams forth from the open fissures and small
hollows, without breaking through or escaping beyond the sides of the
crater. If, however, it does break through, the newly-opened terrestrial
stream generally flows in such a quiet and well-defined course, that the
deep valley, which we term the crater, remains accessible
p 232
even during periods of eruption.
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