The wageworker. (Lincoln, Neb.) 1904-????, 1910-07-15
BIRTH OF A VOLCANO.
Natures Process In Forming a
Mountain of Lava.
THE FORCE OF AN ERUPTION.

UpheavaI That Destroyed the East
Indian Island OF krakatoa In 1888
Propelled an Air Wave Three and q
Halt Times Round the Earth.
Though volcanoes are often spoken
OF az burning mountains. they do not
burn AT all. nor. in the proper sense OF
the word. are they mountains at ALL
A volcano Is really flaw in the crust
of the earth through which the fierce
glowing heat lying below the crust has
managed to burst hole. Through this
hole great floods of melted rock spout
up. Some volcanoes work at inter-
walls; some are In eruption all the time
Az the melted rock Jets up into the
| air and falls it naturally builds itself
into mountain round the hole The
next eruption has to burst it's way
through the heart of that mountain.
The chimney 1t spouts through is usu-
ally called 1.-The pipe"
Sometimes an eruption Is SO fierce
that when the lava another name for
| melted rOck) spouts out 1t is burst into
bits. When it falls it is sometimes as
fine as dust. sometimes the size of Gin
ders. Most volcanoes indeed. are SIM
ply gigantic cinder heaps.
When the force is not SO great the
lava in the pipe simply bubbles over
and flows down the sides OF the noun.
tain. exactly as porridge boils over the
edge OF pot. AS lava Is liquid. the
slope of a lava volcano Tor lava cone
as it Is usually called, is always very
gentle. Failing cinders. on the other
hand. pile themselves up quite steeply.
A lava cone. then. is always less steep
than a cinder cone.
| And q volcano never burns. What
looks like flame is only the glow Of
the white hot lava on the clouds OF
steam. The more steam there is fore
ing Its way up the pipe the more the
lava bubbles. Just as IN the case OF
is very great. then you have the lava
blown to bits and falling as cinders.
while the mighty clouds OF steam rise
high above the mountain. 1t is this
steam that IL mistaken for smoke.
Sometimes cone sends out lava and
cinders alternately. 80 that you have
a great mountain of cinders bound to-
gether by layers and walls of lava.
These wallis Of lava are due to the
fact that sometimes more lava wants
to come up the pipe than the pipe will
hold. SO the lava bursts its way out
through weak spots In the sides of the
mountain. Etna has no fewer than
TOO Of these cones on its slopes. One
| NJ 10 In
itself. being $50 feet high. Indeed. u
model Of Etna looks as If it were COW
cred with pimples.
When Etna is really reused it Is far
more dangerous than Vesuvius. In
1869 it nearly destroyed the city of
Catania. killing $4,000 people. In 1869
1t found its pipe SO inconveniently
small that it had to crack one of its
sides. This crack was no less than
twelve miles long. At the bottom
white hot lava could dimly be seen
through the clouds Of steam. In 1855
millions Of gallons of boiling water
were shot out Of the Val del Bove.
which Is a great circular pit on the
slope of the mountain. four or five
miles in diameter. its sides being cliffs
|
The greatest volcanic eruption ever
known took place in the East Indies
in 1888. The story makes almost In
credible reading. The volcanic island
Of Krakatoa commenced proceedings
bv blowing half Of itself into thin air
From the opening no less than cubic
mile of rock was shot out.
A column of steam and lava dust
rose into the air to q height six times
as great as that OF Mount Everest. 1t
spread and spread till for hundreds OF
miles around the air was black as mid
night. Sounds as of distant cannonad-
ing were heard 1000 miles off.
Sea waves fifty feet high killed 49,
600 people and were felt as far off as
California. Instead OF an island halt
mile high there was now hole a
quarter of a mile deep. The shock OF
the eruption sent air waves three and
half times around the earth. The
fine dust in the upper atmosphere add
ed for months afterward strange
glow to the sunsets in England and
did not vanish completely for three
years.
The exact cause of the eruptions Is
not known for certain. A popular the
, DRY is that they are caused by water
getting In to the white hot mass which
, is supposed to lie under the outer crus
of the earth. And it is certainly fac
that practically all volcanoes are clos'
to the edge of the sea.
Some lava flows slowly. some quick
. ". vesuvius in 1905 sent out a lavs
to- IN, ho1 ~,
I ed spot four miles off. The size of I
$ lava stream is sometimes gigantic. II
1888 Skaptar Jokull in Iceland emitted
two streams at one time One wa
q forty miles long by seven miles broad
the other fifty miles by fifteen. TIL
Z average depth Of both was about I