Spirit of the age. [volume] (Woodstock, Vt.) 1845-1913, 1884-09-03
WHY THE EARTH QUAKES.
What q Scientist Says Upon
the Subject.
Forces Pent UD Under Us That Would
Smash Us if Loose

Prof. George II. Merriman of Rut-
gers College, New Brunswick, N. j,
has made the crust of the earth a
study, and has written on the subject
lie says:
"While facts enough regarding the
extent 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 com
pared with other earthquakes, yet
something may be added 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 is molten mass, and
that we move around on crust en-
veloping the earth and caused by the
cooling off of this mass on the outside.
1t is undoubtedly true that about
thirty miles below the earth's surface
the temperature is 50 high that every
thing is in melted condition. We
know this, because we have learned
that every fifty feet we penetrate into
the earth there is an increase of tenn
perature of about 10, 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 Il liquid. That would be GER
tain but for the immense pressure on
it. The pressure is estimated at TO-
600 tons on square foot. OF course
scientific men cannot experiment with
matter at high temperature with a
pressure of 10000 tons to square
loot,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 by geolo-
glsts.
GLOW great is the distance through
this water substance we do not know,
but it is certain that its density in
creases more and more, gradually, un-
til the interior of the earth is solid,
probably, from the lnconcevaule pres
sure 1000. 1000, or 5000 miles from
the surface. Sir William Thompson
has demonstrated that the earth must
have core much denser than the land
and water we live on. lie points out
the fact that if shell only thirty
miles thick surrounded molten
liquid mass extending from one side of
the earth through the center to the
other side, then the moon, through
the law of gravitation, would displace
the liquid or gas in the interior of the
earth to such an extent that the earth's
crust would bulge out in the direction
of the moon, making a 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, i'm
perceptible 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 i'm
poses an immense weight on water
substance, which is inconceivably hot.
Now, as to the way an earthquake
may be caused. Suppose moisture
trickled gradually, year after year,
through this crust into the heated
mass. In our atmosphere steam
would be produced. Thirty miles be-
low us the pressure is so great that it
is not likely that steam could be gene
rated. One thing, though; the press
ure exerted in every direction, would
be increased. Some effect must be
produced down there, and it is easy to
see that if one place in the earth's
crust is weaker than another near the
region where the water trickled in,
then the weakest place must stan the
strain 1t is not unreasonable to sup
pose 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.
81 believe this theory has the greater
reason on its side, because earthquakes
are almost always in the region of vol
canoes, and volcanoes are almost always
in or near the ocean.
another theory of earthquakes is
that as the earth is very gradually
cooling off the crust is thickening on
the under side, and crack. or assures
on the under side of the crust many
miles deep may occur in consequence
of the enormous pressure so that the
water substance rushes into a new pos
sition with a force that would knock a
continent out of shape if it took place
on the earth's surface. That motion
would be sufficient to produce vibra-
tion thirty miles distant.
"Whatever the cause Of the recent
earthquake" added Prof. Merriman,
81 think the earth in the region where
it took place has either settled into a
new position or is forced back into an