Millheim Journal. [volume] (Millheim, Pa.) 1876-1984, 1883-10-04
VOLCANIC SURPRISES.
The Theory ofIIsruptions-HOw tney
Ariso-DcIugcs Caused by SNOW.

The Theory ofIEruDtiOns-HOw tney
ArIso-DCIuRes Caused by SNOW.
For a volcano once supposed 10 be
inactive, Vesuyius has prepared some
lively surprises for the dwellers i'll its
neighborhood. It's latest surprise has
been to shake up railroad and destroy
several houses. The people of Hercu-
laneum and Pompeii thought Vesu-
vius extinct until one day it proved in
a very thorough manner that it could
still be reused to activity. Since then
no one has been deceived by its
quietude
Other volcanoes besides Nesuvius
have from time to time INDUCED in
what seems to he the general volcano
propensity of creating surprises. Thus
no one would expect to have mass of
rock of some 5000 cubic feet suddenly
descend upon them from the sky, But
people living nine miles from CotO-
paXi were on one occasion treated TO
such a surprise. The Carthaginians,
when they set out against Syracuse,
were not prepared to cross the fiery
river which, to their surprise, inter
cepted their march at Mount Etna.
They had no boats with which to cross
it.
The great eruption of TombOro sur
prised people for some $40 miles
around, the distance at which the
force of the explosion was heard. They
wondered what was the matter until
they learned of the eruption from one
of the twenty-siX persons who were
saved out of Il population of 10000
Surprises of another kind, fearful
deluges, are the first indications in
many South American districts that
volcanoes whose peaks are in the re-
gion of perpetual snow have suddenly
become active, the deluges being caus-
ed by the melting of great masses of
snow.
1t must also be surprise of beau
tiful, though fearful kind, to see a
fiery fountain play TO height of 700
feet from the side of mountain
Such fountain on Mauna Loa in
1852 was Il magnificent illustration of
volcanic iiSsure, the pressure Of lava
at the crater being relieved 10y this
new outlet. The cracks often seen on
volcanoes, which form dikes radiating
from the center, are created in this
manner. Small extra craters, volca-
noes on volcanoes, which gradually be-
come cone shaped, are found along
these assures.
Another surprise. There is no flame
in volcanic eruptions. as is generally
represented most graphically in
chromos. The suppositious flames
are simply reflection Of the lava on
the cloud of ashes and cinders.
The islands which have occasionally
surprised the inhabitants along the
coast of the Mediterranean by appear
ing suddenly under their very eyes are
the result of volcanic action. But
probably the greatest surprise connect
ed with this subject is the formation of
volcanoes. \ volcano is originally
nothing but a hole in the ground, form
ed often at no elevation by the swell
ing and breaking CT an earth bubble.
The mountain which springs up
around this opening is formed by accu-
mutations of successive eruptions.
The great age of volcanoes which, like
Mauna Loa and Mount Etna, are H.
600 and 1900 feet high, can be readi-
ly appreciated from this fact, and
from the further fact that Etna had
attained almost its present height
when it was observed by Greek writer's
$500 years ago.
A volcano is a furnace on a magnif-
cent scale, the lava which it elects
being molten rock. This rock is so
thoroughly fused by some volcanoes
that the lava is as thin as honey, and
flows with a velocity of fifteen miles
an hour. Sometimes it is spun out in
long, CLASSY threads by the action of
bursting gas bubbles.
While there are two kinds of erup
tions, the quiet and the explosive,
there are many theories regarding the
heat which fuses the rocks into lava.
Many think that the interior of the
earth is in liquid condition, but the
better opinion seems to be that the
lava occurs in subterranean lakes. But
the theorists agree that proximate
cause of volcanic eruption is the con-
tact of water with molten rock.