recorded their experiences. So frequent are the eruptions of the
volcano, however, and so much do they change the aspect of the
crater, that any description remains correct for only a limited
time.

Within the last hundred years the crater has been five times wholly
altered, in consequence of its interior having been completely
blown out, and its walls having crumbled down. When Sir William
Hamilton ascended the mountain in 1756, it had no less than three
craters and cones, one within another. The outermost was a very
wide-mouthed cone. Within it rose centrically another, smaller in
size and narrower in the mouth; and within that again was the third
and highest, having a smaller base and still narrower opening at
the top, whence the greatest volume of vapour ascended. In 1767
this innermost cone merged in the second, which was greatly
enlarged; and by a subsequent eruption the interval between the
first and second was obliterated, so that only a single cone
remained. In 1822 the whole interior of the cone was blown out, and
its walls crumbled down, so as to lower the height of the mountain
several hundred feet. But within the vast gulf, nearly a mile in
diameter, which was thus left yawning open, there soon began to be
formed a new cone, which showed itself erelong above the jagged
edge of the crater. Eventually this cone increased, by the
accumulation of ejected matters, to such an extent as to obliterate
the division between it and the rim of the former crater--thus once
more establishing a continuous cone. Since that time, the cone and
crater have twice undergone similar changes.

The most usual appearance of the crater, when in comparative
repose, is that of a vast circular or oval hollow basin, with