Springfield globe-republic. (Springfield, Ohio) 1884-1887, 1885-03-13
EARTHQUAKES.
Some Theories Regarding Them that Have
Obtained Credence.

The intimate relation between earth
quakes and volcanoes is universally adj
mitted. though earthquakes do occur in
regions which give no indication of
either past or present volcanic activity.
Along the southeast coast of Spain.
however. there is ample evidence of
such activity is past times; and it has
been remarked by a writer on the sub
ject that an earthquake is simply an in
tegrated volcano. As to what. how
ever, is the exact cause of seismological
action geologists have not yet made up
their mind. The mathematicians have
compelled them TO give up as quite I'M
tenable the old idea of thin crust over
molten interior which in its surgings
would break through in the shape of a
volcano. or reproduce in the shell the
huge waves which would swell along
the internal surface. The hypothesis of
a solid shell and solid nucleus with
molten matter between has Jared little
better. The earth. it is now held by the
best geologists and physicists. must be
a solid body to very considerable
depth, if not. indeed, to the core. AT
the same time we may be assured that
the most intense heat exists at no very
great depth below the surface, heat so
great that but for the immense pressure
exerted by the superintendent mass the
matter would actually melt; it is held
that it does occasionally do so when
from any of the many forces which are
at work the pressure is relieved, and
this, according to a certain school,
gives rise to volcanic or earthquake
phenomena.
Others. however. maintain that these
manifestations can be satisfactorily ac-
counted for by chemical and mechani-
cal action. 1t seems to be generally
admitted that great masses of water are
constantly filtering into the depths of
the earth from the ocean-bed: and that
the molten materials which issue from
volcanic rents have absorbed enormous
quantities of steam and other gases.
Prof. Judd tells us we have the most in
disputable evidence. 1T is to the viO-
lent escape of these gases from the molt-
en- rock masses, as the pressure upon
them is relieved. that nearly all the ac-
tive phenomena of volcanoes must be
REFEREED And what accounts for vol
canic action may also account for at
least certain class of earthquakes.
For there may be other causes, most of
them, however. referable to the move
ments which must be almost constantly
taking place in their interior, owing to
the cooling of the earth's crust. Var
iations in atmospheric pressure have
been thought to account for some earth
quakes. and it is noticeable that a sharp
fall of the barometer was observed all
over the south of Spain in the afternoon
before the first great shock, and that
there have since been frequent fluctua-
tions. The mere falling of an internal
cavity would almost certainly produce
vibratory phenomena. Indeed, Prof.
Milne seems to believe that the earth is
full of cavities of all sizes, like a huge
Gruyere cheese, and that, consequently,
vibrations of greater or less intensity
are constantly occurring, as we should
find had we weinstruments delicate enough
to measure them. But it is possible,
perhaps, to have seismographs of much
too fine structure, so fine as to record
the vibration of every passing jinriksha.
Essentially the explanation of all these
phenomena seems to be that our planet
is cooling body, and they will only
cease when every particle of heat has
left the heart of our old mother. when,
also, geologists tell us, there will be no
more sea, when the air itself will have
vanished, and the earth will be rs dead
yln