The morning news. [volume] (Savannah, Ga.) 1887-1900, 1900-02-11

! 4 lISt 1t was nOteu tilaL any HltINtu fOch
shrinks in general to the amount of about
| 10 per cent of its bulk In soidifying; and,
! la consequence of this. tends to sink as 1t
/ freezes. This tendency to settle down IN
to an interior fluid would make it possible
| for the crust of generally fluid earth to
attain a greater thickness than about half
/ a mile before 1t would be dragged down by
/ gravitatlon. AS we know that the earth
! is solid for at least twenty miles down
ward, and probably is in that state for
/ several times that depth, the idea of a
thin crust lying as a layer on liquid
/ interior was shaken.
The next attack on the notion of in
ternal fluidity came from the astronomers
I 1t had long been known that the gravita-
| tive attrac tion of the moon on the equa-
torial bulging of the earth, or. rather
| the difference in this pull on the parts
of that mass near to and away from our
| satellite, caused the polar axis tosbe con-
stantly changing it's position The geo
| logical bearings of the movement is found
| in the fact that if the earth were fluid
| except for its crust, the position of the
polar axis would not be altered by the
| attraction but the sphere would change
! shape in the manner of tide, as the
| tiers do under a similar impulse. While
| the problem is complicated and the re-
suits not accepted by all students, IL seems
| from this argument most likely that the
earth is as rigid as the most solid of its
| rocks.
biologists; Views Reviewed.
In face of the evidence as to the diff
! fculties of reconciling the great heat of
! the interior and the election of lavas,
! with the evidence that shows that it can
not be fluid, biologists of this century
| have had to review many opinions which
! they inherited from the last. To begin
WITH they have had to modify their con-
ceptions of solids and fluids so as to clear
away certain misconceptions due to our
! experience with materials on the surface
of the earth. The phrase hard as a rock"
expresses a high order of rightly or re-
sistance to strain, when judged by ordi-
Larry conditions such as we are accus-
toned to; yet, when deeply buried and
subjected to the vast stresses which are
due 10 the contraction of the mass, from
the constant loss of the internal heat
rocks creep in the direction of least
pressure, like wax They twist and fold,
as do sheets of wet paper; they behave
in manner that we are not accustomed
to associate with solidity.
We may see how inadequate are the
common views as to the strength of ma
terials by observing what takes place
when an armor-piercing shot strikes a
thick plate of steel, such as is used to
protect the vital parts of a battleship.
! The shield is made of the most rigid sub
stance that has been contrived. It's re-
sistance is far greater than that of any
rock. Yet, when struck by the projectie
it yields and is pushed aside as earth by
the plow-share. 1t may splash, as mud
when a pebble is thrown upon it,
Inc facts above set forth, well as
other considerations which it is not ueces-
sary to present, have led those biologists
of our time who are concerned with the
difficult problems of the earth's interior to
look upon that realm in a different way
from their predecessors of a hundred years
ago. 1t is now generally believed that
the temperature in the depths, though not
as great as it would be If the rate of in
! crease in heat which we observe in mines
continued downward to the center is still
hot in measure not approached in any
! furnace, or even in the electric arc. That
/ this heat does not resolve the matter into
vapor it would like materials on the
surface, or even bring it to the fluid state
is explained by the action of the pressure
to which it is subjected.
! Pressure That Would SoIidify Air.
We know that pressure tends TO consol-
| idate all substances. Even the relatively
| trifling amount of it that we can apply by
our arts will liquefy air. If we could ex-
| pose this 11uid air TO the weight of a hun
! bred miles of everything rock we may fair
! ly presume that its particles would be so
| driven together that ii would become in a
| manner solid. 1t is true that the heat of
the depths would tend to keep ii from at
tanning solidity; but we may well relieve
that the load would be even more effective
| in bringing it into that state. 1t seems
| likely in a word, that the effect of that
| internal pressure, due to the weight of the
everything matter, in inducing what we
term solidity is greater than the effect of
| the heat in bringing matter into fluid
! condition.
We may bring the points above noted
/ into clear view if we consider what we
! a.nalI A.-1
the cubic foot of matter which lies in the
very center of the earth. 1t is pretty
certain that we should find il hotter than
anything has been on the surface for some
hundred million years: hotter than any
thing we see, except it may be the sur
face of the sun and other fixed stars
We would doubtless find that the atoms
or molecules of the mass were driven
nearer together than the like units of sur
face materials, and that it was more rigid
than glass; yet. under the strains such as
have flexed and tangled the rocks in
mountain folds this bit of the central
| earth would move readily, as all the deem
parts evidently do under like strains.
III we could complete this imaginary OH
serVation by bringing the central bit of
the planet TO the surface, keeping it, dur
ing the 1000 miles of journey in unchansr-
cd conditions of neat and pressure until
II was IN the air, and then suddenly re-
lease its bonds it would explode after tte
manner of fired gunpowder
About Volcanoes
There is the evident question as to the
relation of volcanoes to the heated in
terror OF the earth This is stiIl much de-
oated' but opinion is inclining to the con-
clusion that volcanoes are really sinner
fetal in origin; that they have their
source in the outer hundred miles or SO
OF the crust. and not, as was believed at
the beginning of the century. in the cen
tral region. The fact that they are linn
lied while active to the floor of the oceans
and greater seas and to the lands within
"a few hundred miles of the seashores. in
dicates that they are not of very deem
seated origin. The most remarkable ex-
PLANTATION is that they are due to the eff
feet arising from the LAYING down oe
| strata in water.
Such deposits act as a blanket. serving
to hold in the rocks the heat that is con-
| tinually seeking to escape into the cold
Of fba h,a.. mi.