Rock Island Argus. (Rock Island, Ill.) 1893-1920, 1912-11-22
THE earth CRUST
Its Density, Its Thickness and the
Pressure 1t ExertS.

Some writer's have accounted for the
asteroids on the theory that they are
the fragments of a 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 volcanoes-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 &C.
tually explode the old earth like a
veritable bombshell
But that can never happen.
In 1888 Krakatoa. a sleepy old vol
cano on a 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.
II exerted a 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 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 indication 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 rs in passing judgment on the
/ correctness of this theory.
An explosive compound Is a 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.
Among the most powerful high ex-
piosives are nitrogelatin and p!cric
acid. each OF which has a density more
than one and half times that of
water. The products OF their combus-
ton are nearly all gaseous, whereas the
products of the combustion OF ordinary
black guupowder 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
which the heat Of the explosion can
raise them.
The exact temperature OF the gases
liberated by a 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. 1t is probable
however, that nitroglycerin. nitrogela
tin and picric acid. when detonated II
a confined space. exert pressure some
where between 100000 and 5OO.OOt
pounds to the square inch
II we assume that the earth crus
has a density FIVE times that of waite
and that its average thickness is fit!
miles. then it follows that 1t exerts ;
pressure of more than 100000 pounds
to the square inch: If the crust is l
, hundred miles thick. then the pressur,
is more than a million pounds to tn
, square inch-a pressure certainly great
er than the expansive force exerted b.
] the most powerful high explosive
I Plainly. no quantity of high explosive
detonated under the crust OF the cart
! would be able to lift it, and consequent
! ly we know that no world of the siz
OF the earth can ever explode from II
I own pentup internal forces.
If. then. no high explosive force
sufficient to blow up a world the siz
I OF the earth. how can worlds explode
There is only one way in which til
I heavenly bodies can become possesse
: OF sufficient energy actually to blo1
4 up. and that is by collision.
The stars are flying about in spac
s with velocities that range all the wa
from FIVE miles a second to 500 miles
3 second
II two celestial orbs. travelling eac
& ut a velocity of 200 miles a second. me
in a head-on collision they would
q fused and gasifed by the impact. an
y the heat generated would be sufficieI
81 to break up the matter Of both into II
ultimate elements and to expand it int
nebulous haze. This Is. the way 1
4 which science says that new suns. ne
nebulae and new stars are born.-Hu,
Il son Maxim in Youths ComDani