Idaho County free press. [volume] (Grangeville, Idaho Territory) 1886-current, 1910-06-30
BIRTH OF A VOLCANO.
Natures Process In Forming a
Mountain of Lava.
THE FORCE OF AN ERUPTION.
Uphsaval That Destroyed the East
Indian Island Of krakatoa In 1883
Propelled an Air Wave Three and q
Halt Times Round the Earth.

OF as burning mountains, they do not
burn at all. nor. in the proper sense OF
the word. are they mountains at all.
volcano Is really a 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 foods Of melted rock spout
up. Some volcanoes work at inter-
walls; some are in eruption all the time.
AS the melted rock jets up into the
air and falls II naturally builds itself
into mountain round the hole The
next eruption has to burst its 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 tanother name for
melted rock spouts out 1t is burst into
bits. When 1t falls 1t 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 a pot. As lava Is liquid. the
slope of lava volcano TOR lava cone
as 1t is usually called, is always very
gentle. Falling cinders. on the other
hand. pile themselves up quite steepiy
A lava cone. then. is always less steep
than a cinder cone
And volcano never burns. What
looks like fame Ia 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
the porridge. II the pressure Of steam
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. II is this
steam that Is mistaken for smoke.
Sometimes a cone sends out lava and
cinders alternately. 30 thar you have
great mountain OF cinders bound to-
gether by layers and walls Of lava.
These walls 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 it's way out
through weak spots in the sides of the
mountain. Etna has no fewer than
700 of these cones on it's slopes. One
Of them. Monte Rossi is hill in
itself. being $50 feet high. Indeed. a
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 1860
1t found its pipe so inconveniently
small that Ii 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 1853
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 dia meter its sides being cliffs
nearly mile high in places.
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 a cubic
mile of rock was shot out.
A column of steam and lava dust
rose into the air to u 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
Il ct CO n.
ing were heard 1000 miles of
Sea waves fifty feet high killed 49,
600 people and were felt as far of as
California. Instead of an island half
a mile high there was now hole
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 crust
of the earth. And 1t Is certainly fact
that practically all volcanoes are close
to the edge Of the sea.
Some lava flows slowly. some quick.
". Vesuvius In 1905 sent out lava
stream that In four minutes had reach
ed a spot four miles OF. The size of 8
lava stream is sometimes gigantic In
1888 Skaptar JOkull In Iceland emitted
two streams at one time. One was
forty miles long by seven miles broad
the other fifty miles by fifteen. The
average depth of both was about
hundred feet.
Lava cools very. very slowly. excep