Pittsburg dispatch. [volume] (Pittsburg [Pa.]) 1880-1923, 1890-05-04
THE SAFETY VALVES
From Which Escape Pent-Up FAIRIES
Beneath the Earth's Crust.
PECULlARlTlES OF VOLCANOES.
Lava That Flows Mile Minute and Dust
That Sails Far Away.
THE ERUPTI0NS OF OLD VESUyIUS
PECULIARITIES OF VOLCANOES.
THE ERUPTIONS OF OLD yEsUyIUs

IL
cinity of her internal fires by which gases,
steam and lava or molten rocks and min
erals are allowed to escape from the mighty
caldron which boils beneath. A volcanic
eruption is preceded by great rumbiing
noises somewhere under the surface, causing
a swaying of and sickening movement OF all
things terrestrial. In 1896 a puff of smoke
or steam was observed to come out of the
Pacific ocean near Unalaska. Gradually a
mound arose out of the water amid great
flames and earthquakes. and gradually but
rapidly volcano was formed and the
whole country for ten miles around
was illuminated by the mighty
flames, and their reflection on the
black clouds of smoke. Several years after
ward some hunters explored the volcano,
which they found still so hot that they
could not walk upon it. 1t was then sew
erel thousand feet high. An active volcano
will thus in few years erect itself into a
gigantic mountain whose peak will pierce
the clouds.
The eruption begins with the emission of
very fine whitish gray lava dust, which is
caught up by the winds and carried i'm
mense distances over the earth. The dust
has been in a few hours detected in coun-
tries many hundreds of miles frcm the erup-
tion. At 80 miles distance from a volcano
in Central America the ground was covered
ten feet deep with the ashes. A few years
ago alter the tremendous eruption of the
volcano at Krakatoa, in the Straits of Sun
da, dust and mud were thickly scattered
over vast area, while fearful tidal waves
washed the shores of Sumatra and Java.
EFFECT OF THE DUST.
There were remarkable solar phenomena
in Ceylon, South America and elsewhere
attributed to the volcanic dust in suspen-
sion, and in the United States for q long
time the rosy appearance of the sky before
and after sunset was caused by that stu
pendous explosion as we'll as the Alaskan
explosions which were in sympathy with it.
Lava and scoria were elected from Vesuvius
at one time in an apparent column of fire
to the height of 10000 feet. Lava doesn't
always come from the crater or cone, but 1t
bursts out of the sides of the mountain with
tine brightness of the sun and rushes down
the sides at fearful speed, growing from
small stream into a great river.
When earthquakes precede an eruption
the whole neighborhood often becomes
fssured even up the sides of the volcano,
giving the lava an easy escape through the
assures. When great bodies of snow are on
the mountain top the sudden eruption
causes the mountain to become intensely
hot, but the falling of great quantities
of hot stones and water, rapidly mets
the snow and combined with the hot water
from the crater it rushes down the steep de-
clivity in many mighty rivers, ferociously
washing reslstless course to the sea. Even
the solid lava cannot resist them. The side
of crater away from the wind is generally
the highest as more of the scoria is blown
that way. Some craters or caldrons are
perpendicular for from 1000 to 1000 feet
appearing as though everything had slipped
down in straight line and left giant per-
pendicular walls like tube.
In 1888 during a fearful upheaval at
Hecla great lateral fssure formed, through
which ran mighty river which flowed 100
miles with depth of 600 to 1000 feet, and
a width at one place of Is miles. This
stream of lava would have equaled Mt.
Blanc in bulk.
WHEN THE LAVA HARDENS.
The muttering and rumbling and
final heaving of the ground indicate
what is going on down the precip-
itous tube of the volcano which
is gradually filling up with lava. and which
copiously emits great volumes of steam or
gases; but if the filling is not vigorous. the
top of the mass will chill and stop the up
ward movement which resistance causes a
furious disturbance FAR below, until great
explosion from one OF the sides occurs and
the whole boiling mass will pour out with
out going to the top OF the crater
Volcanoes cannot be relied on as being
classed among the dead. They may lie
quiescent for many years and then suddenly
commence again. Stromboli, Cotopoxi and
MANY others have been throwing off hot
stones and steam since time had history;
Vesuvius has been deceisful, lying dormant
for 131 years at one time until the whole
mountain, crater and all, had become covered
with vines and prushwood and was the lair
of the wolf and the wild boar; but suddenly
in 1861 an explosion occurred OF such tre-
mendous violence as to send the echoes back
to the year 79, when Herculaneum and
Pompeii were engulted with hot water
and ashes. 1t had been classed as dead
volcano.
Kilanea is a vast crater on the eastern
side of Mauna Loa volcano in Hawaii. They
are the same mountain, having two outlets.
but entirely independent OF each other
Kilanea is always active, and the SLOWLY
boiling pots of lava can be seen any time of
moderate activity from the slopes around
The streams of lava cool quickly on the sur
face and form hard crusts on which the ad-
venturous can walk within few days
and see through the assures beneath them
the glowing. burning lava.
UPHEAvALs AND DEPREssIoNs.
The country around volcano is often
changed suddenly. During the last century
a volcano appeared in the midst of the great
table land of Mexico and raised a section of
four square miles about $50 feet above its
former level and throwing up many conical
hills, one of them being 900 feet high. At
other places subsidences have occurred. In
1772 mountain In Java, Papandayang.
was partly swallowed, and the residents.
trying in their alarm to escape, were en- |
quilted with their homes and fields. A dis |
trict Is miles long by wide subsided and
soon disappeared.
Volcanoes throw out vast quantities of |
water. 1t would seem that they are con- |
nected underneath with the sea, or great |
volumes OF subterranean water. The water |
comes into contact with the fiery bodies of
lava, and, forming steam, bursts its confine-
ments, accompanied by preliminary
rumblings and ending with tremendous |
outburst which shakes the world. The |
South American volcanoes throw out fish. |
while one In Java throws out hot acid water.
Some throw up mud. The eruptions of |
Vesuyius are preceded bv the dminuition Of
the water In the springs and wells in the |
district, but better indication is from the |
tremors Of the ground. The vapors from
the crater increase while the lava boils /
steadily up in the tube and great puffs of |
smoky rings are shot heavenward until |
they form a column two miles high above |
the crater. Great fiery stones shoot high up |
in the air, and sometimes fall beyond the |
base OF the mountain. The increase and de- |
crease of the convulsions can be determined |
by the violence of the explosions which ex-
pei these rings.
Dorrprrrr MN