the
discharge being like that of shot from a fowling piece; the fragments,
varying in size from small, shotlike bits to masses larger than a
man's head, were shot up sometimes to the height of fifteen hundred
feet above the point of ejection. The wind, blowing at the rate of
about forty miles an hour, drove the falling bits of rock to the
leeward, so that there was no considerable danger to be apprehended
from them. Some seconds after the explosion they could be heard
rattling down on the farther slope of the cone. Observations on the
interval between the discharge and the fall of the fragments made it
easy to compute the height to which they were thrown.

At the moment when the lava in the pipe opened for the passage of the
vapour which created the explosion the movement, though performed in
a fraction of a second, was clearly visible. At first the vapour was
colourless; a few score feet up it began to assume a faint, bluish
hue; yet higher, when it was more expanded, the tint changed to that
of steam, which soon became of the ordinary aspect, and gathered in
swift-revolving clouds. The watery nature of the vapour was perfectly
evident by its odour. Though commingled with sulphurous-acid gas, it
still had the characteristic smell of steam. For a half hour it was
possible to watch the successive explosions, and even to make rough
sketches of the scene. Occasionally the explosions would come in quick
succession, so that the lava was blown out of the tube; again, the
pool would merely sway up and down in a manner which could be
explained only by supposing that great bubbles of vapour were working
their way upward toward the point where they could burst. Each of
these bubbles probably filled a large part of the diameter of the
pipe. In general, the phenomena recalled the escape of the jet from a
geyser, or, to take a familiar instance, that of steam from the pipe
of a high-pressure engine. When the heat is great, steam may often be
seen at the mouth of the pipe with the same transparent appearance
which was observed in the throat of the crater. In the cold air of the
mountain the vapour was rapidly condensed, giving a rainbow hue in the
clouds when they were viewed at the right angle. The observations were
interrupted by the fact that the wind so far died away that large
balls of the ejected lava began to fall on the windward side of the
cone. These fragments, though cooled and blackened on their outside by
their consider