The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1869-08-06
VOLCANIC.

A New Theory of Earthquakes and Volcanoes.
An original and highly ingenious theory of
earthquakes and volcanoes is propounded at
great length in BiucklcO0d for July. The sub
stance Of it may be thus briefly stated:-The
author assumes, on the strength of numerous
ascertained facts, that the earth has a zone or,
more accurately speaking, shell of electric
action, extending all around the globe, to a
depth of several miles. (The sun is the great
source from which the electricity of the earth
is derived and the weakness OF rintensity of the
latter depends on the solar action, but the laws
which govern the variations are not yet under
stood.) This zone corresponds to an electric
zone of six OF eight miles thickness in the at
mosphere, and the interplay of the two causes
some of the most brilliant lightning effects of
thunder storms, in the severest of which the
flashes are chiefly sentupwards from the earth
itself. But as the atmosphere has its own
electrical agitations, in the form of distant
thunder clouds, which, becoming overcharged
with electricity, rLg gain their equilibrium by
lightning flashes OF sharp electrical dis
charges; so has the earth its own electrical
phenomena the effects of which are mainly
confined to its own bosom. Earthquakes. the
author claims, are results of the grander cleo
trical disturbances which from time to time
take place i'll the zone of rocks Immediately
subacent to the earth's surface. They are
circumstances the electric currents which re-
gularly circulate in the earths crust, ebb and
flow as quietly and nOiselessly as similar cur
rents usually do in the atmosphere. But,
occasionally, when electric action to an un-
usual extent is developed in the crust, the
steady flow Of the currents is broken, and vio-
lent disturbances necessarily follow.
The conductive power of the rocks becomes
inadequate to pass the currents with sufficient
70 ha
and the electricity accumulates at points
where the resistance is greatest, until it ac-
quires the power requisite to overcome the
obstacle and then forces passage explosively,
or by grand discharge more terrible, some
times than a volley from the concentrated
artillery of the world. A vast heat is gene
rated at the same time electricity being the
greatest heat-developer in nature), the rocks
are in some cases actually fused, subterranean
lakes and rivers are instantly converted into
steam, and the result is a rupture of the sub
jacent rocky strata, the effects of which reach
! the surface, producing the various phenomena
of the earthquake, including those of volca-
! noes, such as the outburst of molten lava
! hot water, and clouds of steam. The known
active volcanoes are only vents which the
subterranean electric action has made for
itself in regions OF localities where the action
is strongest and most permanent.
The author dispenses with the theory of
molten interior Of the earth, adopted by Sir
Humphrey Dayy and other distinguished OBJ
servers and philosophers to explain the same
| phenomena. (1his is commonly known as the
chemical theory. Is supposes that potassium,
sodium, magnesium and the metallic bases of
all the earths and alkales exist below the crust
in an isolated condition; ready to combine,
with violent chemical action, with the oxygen
| of water or the atmosphere that might pene-
trate the assures. The reaction of these ee-
ments would be attended with intense heat
and the formation of highly explosive gases
Combinations of immense masses of sulphur
| with various gases would pro-
| duce similar effects. On a suffici-
emily large scale these reactions would
shake and upheaye the earth and eject vast
quantities OF what is called lava from existing
volcanoes, or make new volcanoes. There
may possibly be tidal movements in the molten
interior, caused by the attraction of the sun
and moon, like those of the ocean, and by
those movements stupendous chemical reac-
tions may be produced. Changes of tempera-
ture on the outside of the earth may also
be followed by disturbances in the inside.
The crust supposed to cover this molten sea
is estimated to be thinner in some places than
in others-its maximum thickness not being
over 20 miles-and it is coniectured that at
those parts of the earth most visited by earth
quaRes and volcanoesthe crust is the thinnest }
He attributes to his shallow electric zone
the subtenanean heat observed in mines and
IN the waters of artesian wells-phenOmena
usually explained on the hypothesis of a CEN
tral fire, the heating effects of which are sup
posed to extend to within short distance of
the surfvce Of the earth, The electric cur