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ascent of the volcano. The cinder cone has a diameter at its base of about 
one and one-half miles. It rests on a gently sloping hill, while its own 
angle of elevation is about 30°. This cone or new mountain is about 1,200 
feet high and terminates in a comparatively level top, varying in diameter 
from 500 to 1,000 feet, and now about 4,200 feet above sea level. 
In 1890 as we approached the summit we felt that it was shaken at 
intervals of about thirty seconds. Soon we noticed that the tremors were 
accompanied by a peculiar sighing and explosive sound. At the summit 
a cone of freshly-ejected material had been formed, forty or fifty feet 
*high and 150 to 200 feet in diameter at the base. At each explosion a 
fountain of semi-fluid lava was projected to the height of 100 feet above 
the top of the crater. Most of this material rained back into the crater’s 
mouth, into which we could not look, but much of it fell in fragments on 
the outside. 
In 1891 the top of the cinder cone had undergone a complete change. 
The small cone surrounding the crater had entirely disappeared. In its 
place was a cavity 200 feet across and of unknown depth. The mouth 
of this cayity was filled with vapors and dark sulphurous gases which 
completely hid the boiling lava far below, and which, streaming into the 
air, gave to the mountain the appearance of smoking. But standing on 
the edge of the chasm a continual din deafened us and an occasional 
heavier explosion smote our ears. 
In the Atrio del Cavallo, a deep valley to the north, between Monte 
Somma and the cinder cone, we could see the glow of fresh lava as it 
flowed from the mountain’s side. During the previous year the hydro- 
static pressure of the molten, liquid mass rising so high in the crater had 
forced an exit through the base of the cinder cone. 
In 1894 lava no longer issued from the recent vent towards Monte 
Somma. During the intervening period, after the great pressure of 1890 
had been removed, it had flowed more and more slowly until it began to 
clog the opening and finally sealed it completely. This vent, which in 
1890 was in the direction of least resistance, must now be one of the 
strongest parts of the mountain. Thus one by one the weaknesses of the 
cinder cone are patched up until the conditions of strength are prepared 
which will compel the lava to flow out of the very top. Soon thereafter 
will follow a great eruption. Just as in 1891, there was in 1894, an open 
central crater, but by its continual ‘‘working’’ the mountain had filled 
up the bottom of the cavity, and the surface of the molten lava had risen 
