The Washburn times. [volume] (Washburn, Wis.) 1896-1976, 1913-01-23
THE EARTH CRUST
Its Density, Its Thickness and the
Pressure It ExertS.
A BAR TO WORLD EXPLOSION.

Ours, With All Its Pentup Fiery
Volcanic or Gaseous Forces at Work,
Could Never Be Blown TO Fragments.
Some writer's have accounted for the
asteroids on the theory that they are
the fragments of world that from
some unknown cause has been explod-
ed In its orbit. Similarly. many have
thought that perhaps at some distant
time. when the seas shall have been
drunk up into the cracked and thick
ened crust of the age shrunken earth
and the vokanoes-thOse vents OF the
fiery interiOr-shall have become chok-
ed and extinct. the pentup gases gener.
ated from the descending moisture by
the still great internal heat may ac'
tually explode the old earth like a
veritable bombshell.
But that can never happen.
In 1883 Krakatoa. sleepy old vol
cano on small island in the strait
Of Sunda between Java and Sumatra
began to show marked signs Of uneasi
ness. Round the volcano the quaking
earth opened enormous assures In the
bottom of the sea. down which rushed
Niagaras of water Then the assures
closed and confined the engulfed food
In the hot subterranean depths. The
water was quickly converted into
steam. the steam into ASSOCIATED
gases. without room for expansion.
1t exerted pressure equal to that
of the strongest dynamite.
The great chimney of KrakatOa.
sealed since the memory OF man.
barred the normal path Of escape
Higher and higher mounted the pres
sure under the huge mass of the vol
cano: then. Of a sudden. came a blast
that actually shook the earth. Never
before in historic time had there been
such a shock. The whole top OF the old
mountain was blown into the sky. The
recoil was distinctly felt clear through
the terrestrial ball
This great cataclysm has been cited
as an Indicate of the power of the
pentup forces that may some day dis
rupt the earth itself. Let us examine
the underlying principles that must
guide us in passing judgment on the
correctness of this theory.
An explosive compound Is combust-
lble combined mechanically or chem
ically either with oxygen or with an
oxidiZing substance that will burn with
out the help of atmospheric oxygen.
hn nj hirl nv
plosives are nitrogelatin and p;cric
acid. each of which has density more
than one and half times that Of
water. The products of their combus-
don are nearly all gaseous. whereas the
products of the combustion OF ordinary
black sgunpowder are less than half
gaseous. The larger part is the solid
matter that makes the smoke.
The energy that high explosive can
exert depends on the volume of the
gases liberated and the temperature to
which the heat of the explosion car
raise them.
The exact temperature OF the gases
liberated by high explosive at the In.
slant Of detonation is not absolutely
known. but may be approximately
learned through chemical experiment
Nor is the amount Of pressure known
with absolute certainty. It is probable.
however that nitroglycerin. nitrogela-
tin and picric acid. when detonated IL
q confined space. exert pressure some
where between 100000 and 100000
pounds to the square inch.
If we assume that the earth crust
has density five times that Of water
and that its average thickness Is fifty
miles. then 1t follows that 1t exerts
pressure Of more than 100000 pounds
to the square inch; II the crust is a
hundred miles thick, then the pressure
Is more than million pounds to the
square inch-a pressure certainly great
er than the expansive force exerted by
the most powerful high explosive.
Plainly. no quantity of high explosive
under the crust Of the earth
would be able to lift 1t. and consequent
" we know that no world Of the size
Of the earth can ever explode from its
own pentup internal forces.
If, then, no high explosive force is
sufficient to blow up a world the size
Of the earth. how can worlds explode?
There is only one way in which the
heavenly bodies can become possessed
of sufficient energy actually to blow
up, and that is by collision.
The stars are flying about In space
with velocities that range all the way
from FIVE miles second to 500 miles
second.
II two celestial orbs, travelling each
at velocity Of 200 miles a second. met
in a head-on collision they would be
fused and gasified by the impact. and
the heat generated would be sufficient
to break up the matter of both into Its
ultimate elements and to expand It into
nebulous haze. This is the way In
which science says that new suns. new
nebulae and new stars are born.-Hud-
son Maxim in Youths Companion.