The Delaware ledger. (Newark, Del.) 1879-19??, 1885-06-20
About Earthquakes.

thousand IN CalaDrlan caTlltudhe |
Of 1878. "The earthquake catalogue |
of the British association" II very
complete record, embraces between
six and seven thousand earthquakes
between the years 1901 B. c, and A.
d. 1912, in which it is estimated
that thirteen millions have persisted.
The phenomena attendant upon
earthquakes are as various as their
extent is broad. Appearances in
the heaven or changes in the atmos-
phere, irregularities in the season,
violent rains at unusual seasons,
and reddening of the suns disk,
have all been described as Incl
dental occurrences, but it is doubt.
full if they have any real connection
with the earthquake. Not so with
the underground noises, which
nearly always precede, accompany
or follow shock. In some earth
quakcs they are likened to chains
being dragged about, increasing to
thunder tones in others the sound
is like the rumJling Of carriages,
growing louder until it equals the
largest artillery.
In severe earthquakes there is al
most invariably a trembling, then n
pronounced shock, and then atrem-
bling again, which gradually grows
impreceptible. The whole area of
the surface affected is not moved at
at once, but by an earth wave or
true undulation of the solid crust of
the earth. The influence of this
earth wave is often communicated
to the sea when the earthquake is
near the shore. The sea swells and
retires slightly from the beach, and
then u great wave rolls in upon the
shore. The phenomena of theseup-
heavals and of volcanoes are most
intimately connected. Although the
earth must be mainly solid, it is be.
licvcd to be a honeycombed struc.
turc, and that the cavities contain
in many places lakes of molter
rock. between which and volcanoes
are orificcs of communication. Int
these cavities water, sinking dow
through creviccs from the ocean o
the land, must be constantly fiddinl
its way, and the steam thus gcncr
ated exerts such enormous pressure
as to force the molten matter to tn
surface, itself mingling and escaping
with it. When a mass of water i
suddenly precipitated into no
cavern the explosion of steam vii
, cause an earthquake conclusion
: and where there is no vent may b
sufficient to convulse and rende
the superintendent strata.
No part of the earth S surface
free from these terrifying visitatio
and the ocean itself is not free fror
them. On the nineteenth of OctC
Der, 1870, occurred the most consiC
cradle shock that has been obserN
ed in our middle and eastern state
( during the present century. I'll
/ source of this disturbance has bee
, traced, with some probability, to IL
volcanic region fifty to one hundrc
miles northeast of Quebec, Fro
this region the shock spread to 5
John, New Brunswick, and then
was felt westward to Chicago an
- southwark to New York. The V,
ocity of the wave or shock W
about fourteen thousand feet p
minute.
The most severe Earthquake tn
has occurred in the Middle Stat
was that of the eighteenth of Nc
ember, 1856. 1t was probable pl
mulgated from the same centre
that which destroyed Lisbon
weeks before. In Massachusetts
began with n roaring noise Ii
thunder, followed by swell of
earth like that of a long rolling s
In 1871 occurred the famous ear
quake of New Madrid, Mississir
which created the so-called 81
country in the valley of the NJ
. issippi, while California has f
quently suffered.
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