The McCook tribune. (McCook, Neb.) 1886-1936, 1910-06-16
OF A VOLCANO,
Natures Process In Forming a
Mountain of Lava.
THE FORCE OF AN ERUPTION.
upheavaI That Destroyed the East
indian Island of Krakatos In 1888
Propelled an Air Wave Three and a
Half 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.
A 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 a hole. Through this
hole great foods of melted rock spout
up. Some volcanoes work at inter
walls; some are i'm eruption all the time.
As the melted rock jets up into the
air and falls II naturally builds itself
into a mountain round the hole. The
next eruption has TO burst its way
through the heart Of that mountain.
The chimney II spouts through is usu-
ally called 1.-The pipe"
Sometimes an eruption Is so fierce
that when the lava another name for
melted rockI spOutS out II is burst into
bits. When it 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 q lava volcano Tor lava cone.
as it is usually Called is always very
gentle. Falling einders. 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 fame is only the glow Of
the white hot lava Oh the clouds of
steam. The mor steam there is fore
ing its way up the pipe the more the
lava bubbles. just as in the case Of
the pOrridge. If 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. 1t is this
steam that is mistaken for smoke.
Sometimes a cone sends out lava and
cinders alternately. so that you have
a 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 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
of them. Monte EOSsi. is Il hill in
itself, being $50 feet high. Indeed. a
model of Etna looks as if ii were GOV
cred with pimpIes.
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
it found its pipe so inconveniently
small that it had to crack m 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 1850
millions of gallons of boiling water
were shot out of the Val del Bove,
which is a great circular pit Oh the
slope of the mountain. four or five
miles in diameter, its sides being cliffs
nearly a 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
miIo Of rocL m1S Shnt ont
A column of steam and lava dust
rose into the air to a height six times
as great as thar 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 3d.
600 people and were felt as far of as
California. Instead of an island half
a mile high there was now a hole a
quarter Of a mile deep. The shock OF
the eruption SEM air waves three and
a halt times around the earth. The
fine dust in the upper atmosphere add
ed for months afterward a strange
glow to the sunsets in England and
did MOI vanish completely for three
years.
The exact cause of the eruptiOns is
not known for certain. y popular the
ory 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 it is certainly a fact
that practically all volcanoes are close
to the edge of the sea
Some lava flows slowly. some quick
". Vesuvius in 1905 sent out a lava
stream that in four minutes had reach
ed a spot four miles off. The size of q
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 a
hundred feet.
Lava cooIs very. very slowly. except
on the surface. which coOls at once.
1t is an extremely bad conductor Of
heat. Twenty years after a stream Of
Ioro ,rae cont ort from JOruIlO in Mex