Burlington hawk-eye. [volume] (Burlington, Iowa) 1845-185?, 1846-09-17
On Earthquakes and their Causes.


A, the last annual meeting of the asso.
citation Of American biologists and na,ur-
alis,s, held at New Haven, Prof. Jackson
delivered lecture on earthquakes. and
their causes, which attracted much atien.
ton.
lie began by showing ,ha, the centre
OF The earth was in the condition Of liquid
fire. lie supposed the earth to be origin
ally. as it were, a great drop Of lava, and
that its present form-being hauened at
the ends and bullying at the centre-was
given TO it by its rapid revolutions and
motion through space In process Of time
the outer surface of the earth became
cool. and formed a crust, which from
shrinking became uneven and broken
That The centre of the earth was mass
Of fire. he proved by reference TO obser.
vatons made in deep mines, wells, &c.
The hot springs in various parts Of the
world derived their temperature from this
internal fire. /, had been ascertained
| that as the centre Of the earth is approach
ed, the hea, increases. lis surface was
continually and gradually undergoing a
change One shore Of the Baltic is slowly
sinking. and the other rising at the rate
Of four feet in century. The coral Is
lands and reefs are constantly sellling
down, and new deposites are thrown upon
them, and thus their bulk is continued.
The lecturer then proceeded to notice
the more violent changes on the surface
of the earth. called earthquakes. He
showed that the motion was regular, like
the roll of the wave. and that the ground
had the same undulating motion as the
sea. A whole continent would be affected
bv passing wave of motion, the wave
travelling al the rate of about thirty miles
in minute. The Lisbon earthquake
was felt throughout Europe. and enor.
nous waves were sent across the ocean
in regular surges; the distance was travel
led al the rate of twenty five miles min
ute. The earthquake which shook the
valley of the Mississippi few years ago.
rolled in three distinct waves across the
country 10 the Atlantic shore, as he had
ascertained by his own investigations.
The crest OF The wave reached across the
continent, from the north east TO the south
ives, and the roll was towards the south
and towers Of buildings, when rocking,
will determine the direction in which the
earthquake, or the wave of liquid fire, is
moving.
i The speaker, in further proof Of his
position. referred to the action of the sea
; in various earthquakes, and dwell partc.
ularly upon the facts in regard 10 the
J destruction BY earthquake of Port Con-
, ception. in Cuba. in 1895. The harbor
5 was emptied of lis water three successive
a times. These commissions in the earlh's
interior tended to alter permanently the
: earth's surface, and 10 leave the crus, in
4 alternate arches and depressinns. This
unevenness was effected in this way: the
!. earth crust became broken by each wave
! and The molten lava rushed up 10 fill the
= chasm, and, soon becoming cool, the arch
f was permanently fixed. This condition
h of the earlh's surface could be seen in a
. thousand places where excavations and
e mining operations have been carried on.
e and il could also be seen in the various
e mountain ridges all over the earth. Thus
r The course OF rivers were changed, and
5 lakes and seas were empiied Of their wa.
+, ers.
= The professor related many other facts
e bearing upon the subject, which were full
r Of interest. The changes in the earth
e surface by the violence Of earthquakes,
f enabled the geologist TO determine many
important facts in regard TO the time re-
e quired for certain deposites and changes,
: during the more quiet progress of Nature
| IL IF tha rln ha fl hn
: residence of man. In illustration OF the
mode in which the earth recorded its
$ changes. the speaker exhibited what he
IS called the Miners Almanac which was
# hard substance taken from one Of the
c coal mines Of Great Britain. During the
h working days. air, in the process of ven-
,r tilation. is driven through all the recesses
e Of the mine, and this air carries with il
!. fine PARTICLES Of coal dust, which settle
il upon the lime dust that gathers Upon the
!. surface Of the pools Of water Within
is The weight of these accumulations causes
e The deposie 10 sink and thus record il
=. made of every working day by black
: strickland Of every night by white
II streak. Sundays and holidays are marked
in a similar manner, for. when there is no
labor for twenty four hours, broader
white streak is exhibited than when labor
= ceases for the nigh. And, again, when
- Sunday has been employed in labor
the black streak is widened in the same
manner. In similar way the earth re-
cords the time required for many Of the
=, changes which the surface undergoes.
:, Disnnreru of GLnSs-.As some mer