Daily Kennebec journal., 1884-09-29
mrsfellaneuus.
Why the Earth Quakes.
THE FORCES SUPPOSED To BE AT WORK
THIRTY MILES BENEATH Us.

Professor George H. Merriman, of Rut-
gers college, New Brunswick, has made
the crust Of the earth study. and has
written on the subject. He says:
while facts enough regarding the ex-
tent of the earthquake of Sunday have
not come to hand to enable me to speak
on the direction of the earth wave or its
peculiar features as compared with other
earthquakes. yet something may be said
as to the latest convictions of students on
the nature of the earth below the point any
man can penetrate That may lead us to
guess intelligently at the cause of earth
quakes, yet something may be said as to
the latest convictions of students of science
on the nature of the earth below the point
any man can penetrate. This may lead
us to guess intelligently at the cause of
earthquakes, yet something may be said
as to the latest convictions of students OF
science on the nature of the earth below
the point any man can penetrate. That
may lead us to guess intelligently at the
cause of earthquakes.
| You know the long received theory
OF the nature of the interior of the earth
was that it was moulton mass. and that
we move around on a crust envelOping q
the earth and caused by the cooling off of
this mass on the inside. 1t is undoubtedly
true that about thirty miles below the
earth's surfece the temperature is so high
that everything is in a melted condition
We know this because we have learned
that every fifty feet we penetrate into the
earth there is an increase of temperature
of about one degree, and at distance of
thirty miles the heat is so great that any
substance we know of would melt.
Perhaps the melted mass is in the form
of liquid. That would be certain but for
the immense pressure on 1t. The pressure
is estimated at 10000 tons on a square
foot. OF course scientific men cannot
experiment with matter at a high temper
ature with pressure of 10000 tons to a
square foot, so we can only guess what
may be its condition. In talking about
this melted mass thirty miles under us.
the term water substance is used bv
geologists.
/ "How great is the distance through this
water substance we do not know, but it is
ceratn that its density increases more and
more, gradually, until the interior Of the
earth is solid, probably from the incon-
ceivable pressure 1000, 1000 or 5000
miles from the surface Sir William
Thompson has demonstrated that the
earth must have a core much denser than
the land and water we live on. He points
out the fact that if shell only thirty miles
thick surrounded molten liquid mass
extending from one side of the earth
through the centre to the other side,
then the moon, through law of gravita-
ton. would displace the liquid or gas in
the interior of the earth to such an exteat
that the earth's crust would bulge out in
the direction of the moon, making tide
in the solid crust of the earth, as certainly
as the skin of an orange bulges out when
you squeeze the fruit between the palms of
your hands. And this would be evident
to us because the ocean tides would be
almost, if not quite. imperceptatle to us.
To withstand the attraction of the moon,
the earth. Sir William says, must be as
rigid as steel.
$50 we have the theory that the crust
of the earth floats on and imposes an i'm
mense weight on a water substance, which
is inconceivably hot. Now .as to the wav an
earthquake may be caused. Suppose mois-
ture trickled gradually, year after year,
through this crust into the heated mass.
In our atmosphere steam would be pro-
duced. Thirty miles below us the pres
sure is so great that it is not likely that
steam could be generated. One thing.
though the pressure of 10000 tons to
the square foot, pressure exerted in
every direction, would be increased. Some
effect must be produced down there, and
1t Is easy to see that if one place in the
earth's crust is weaker than another re-
gion where the water trickled in, then the
weakest place must stand the strain 1t
is not unreasonable to suppose that this
pressure below might be so great that the
earth's covering was shifted little to
adapt itself to the pressure from below
This shifting of the crust is, in fact, the
earthquake.
Il believe this theory has the greater
reason on its side. because earthquakes
are almost always in the region of volca.
noes, and volcanoes are almost always in
or near the ocean.
Another theory of earthquakes is that
as the earth is very gradually cooling of