Smyrna times. [volume] (Smyrna, Del.) 1854-1987, 1907-11-20


The idea that the interior of the globe
is composed of flowing lava has long
since been abandoned, but the picture
that modern science offers of the in
side Of the earth is hardly less ap-
palling. All investigations unite to
prove that the heat increases as we de-
scend deeper in the terrestrial crust
at such rate that forty or fifty miles |
down no substance with which we are |
acquainted could remain unmelted. And |
yet the same science tells us that the |
core of the globe is enormously more |
rigid than the hardest steel This ap-
parent contradiction is due to the ire
mendOus pressure inside the earth. No
rock and no metal can remain there in
the state in which we see it. on the sur
face. It's molecules must lose the ad-
herence characteristic of solid bodies
in consequence of the heat, but still
they are not free to flow like an Ordi-
nary liquid, because of the compression
to which they are subjected.
The phenomena of earthquakes have
given wonderful information about the
internal state of the globe. All OBJ
servations show that the shocks of
earthquakes are confined to thin up
per shell. They originate at a depth
of only few miles at the most. But
the vibrations which they set going
are felt all through the earth, often ex-
tending to the antipodes The great
core, held rigid by the pressure, is eX-
tremely elastic. and it responds to a
shock like a ball of steel or of glass.
| The density of the earth increases to-
ward the center 1t is only in the up
| per part of the crust that local move
ments can take place, causing shocks
| and changes of level at the surface
Deeper down everything is gripped and
immovable, except, as already re-
marked, that the molecules of the rocks
and metals there are subject to vibra-
ton like those of bell against which
a blow is struck.
But this Isl not all. Whenever a local
release from the pressure is brought
about by changes near the surface the
potentially liquid but effectually solid
core at that point may suddenly be-
come fluid and gush forth through a
volcanic throat or other vent. But
such effects cannot extend to any great
depth. Nothing comes to us from the
vast interior mass. That remains a
perpetual mystery, far beyond the
searching hand of science. Indirectly,
however, we may learn much about it.
Astronomical considerations throw a
great deal of light upon the subject.
We see that through the planetary sys-
tenn rotating globes are fiattened at the
poles. The same thing is true of the
earth. It's equator bulges; its polar
regions are drawn inward. Mechan.
ical laws assure us that the cause Is
to be found in the fact that the earth
and the other planets have assumed
shape under the influence of the cen
trifugal force of their rotation. That
force is necessarily greatest at the
equator. Beginning as completed mol
: ten bodies, they have commenced to so
4 lidify at the surface after having as
: sumed an ellifordal form due to thei
\ rotation.
;. Another very significant fact is tina
IS the shape Of the earth corresponds wit
d that which a globe rotating with it
velocity would have If composed o
materials arranged to their density
that is to say, growing denser towar
the center. The heaviest material
must be deep down in the globe; tn
lighter materials have remained at tn
surface. This again corresponds wit
the facts of observation. We kno7
the total weight" and the averag
density of the earth. 1t weighs" 81
sextillions of tons, and its averag
density is five and half times that {
water But the substances composiu
the crust Of the earth have an averas
4 density of twice that of water.
~ follows that the heaviest things in Il
,a4 earth, on the average, exist deep wit
an in it's exterior For all that we CO
1 tell its inner core may be wholly m
r. tallic. At the center there is probab
sl an enormous aggregation of dense N
90 / tallic substances.
ire An indication that the inner parts
sss the earth consist largely If not main
Oil or iron Is to be found in the ma
his netism of the globe. The earth is
M great permanent magnet If we cou
* learn the facts it might turn out til
90, iron is the most abundant substar
es. in the solar system and perhaps
The the whole universe. The majority
'st. the meteorites that fall upon the ear
: consist Of solid iron. Blow the ea1
, to pieces and in the resulting Gle
I Of fragments the rocks that we
la. familiar with would be almost imp
ceptible. There would be a rain
en- iron and other metals descending VI
the moon and upon any other attra
ing body in the vicinity.
This view of the interior OF
,n globe disposes of the notion, so pict
III esauely developed in one OF Ju
yerne's romances, of the existence
vast cavernous openings in the IL
rior of the earth. Such void spa
though on no large scale, may e1