National Republican., 1886-09-02
Thenrlna Of EnrthnnnI,ns.

Nights" and made up in diversion what
they wanted in scientific method. Even
such an encyclopedia as Uncle Aristotle
evolved the causes, conditions, and results
of natures earth upheayals from the depths
Of his own consciousness, anticipating the
well established manner of metaphysical
Teutons when treating of ontologlcal and
kindred matters Of the clouds.
The title Of one dissertation is GA brief
and correct account Of an earthquake by
whichlupwards OF $4,000 persons porished,
together with an account Of the weather for
a month previous and subsequent to this
phenomenon. To which is added an ale
gorlcal description Of the present state Of
the royalists in that country" This pam
phlet, published about 1867, contains
twenty pages of such absolutely impartial
criticism and description that the comments
on earthquakes might have been applied to
royalists, and vice versa, without the slight
est detriment to human knowledge.
Earthquakes and Volcanic Eruptions;
Their Causes and Times OF Occurrence Dis
cussed," by Richard Mansell, Rock Island,
ILL.,, 1870, is n remarkable recent work. The
gifted author, postulatlng "that all our
epidemics are produced under these differ
ent kinds Of planetary phenomena, which
appear as different kinds Of sickness in the
different seasons Of the year." proceeds to
include earthquakes in the category OF
epidemics, and lucidly illustrates the gen.
eral principle as follows! "On June Is, 1859,
Mr. Henry Raymond, editor OF the New
York Times, dled suddenly. A very worthy
citizen, Ilibbeard More, Of Rock Island
county, H., died suddenly at his home on
June Is, tChich icds the same day hH Mr..
Raymond died. About the same
time, Or two days prcriouS TO this,
on June 10, Mrs. Dunlap fell dead at the
Boston peace jubilee. The moon was In its
perlgee on the 16th-the yery same day.
Such cases as the above are likely to happen
In excess in years that great comets pass their
pcriheiiOnS and dphelions, or gears Of total
eclipseS Of he sun, or gears Of many eclipses
| Of The SUM-" This is the simplest statement
that we have seen upon the subject, aud IL
the reader fails to comprehend II he will
have to wrestle with the less general dis
coveries of experlmentallsts.
After consulting Mallets great book on
the "Neapolitan earthquake of 1857" and
lie Conte's "Elements of Geology" we find
clear tpitome of both In an article con-
tributed 10 the Encyclopedia Britannica
by +. w. Rudler, f. G. s., professor OF
chemistry and mineralogy at University
College, Wales.
Mr.. Rudler says It is only within twenty
| years that the phenomena Of seismology-
| a..N ,.I1
| quake-has been subjected to exact investi-
cation. In England the earliest work
worthy OF mention is DR.. Robert Hooke's
"Discourse on Earthquakes" written In
1868. This is unsatisfactory as are also the at
tempts OF Priestley and some other writer's
Of the last century to connect the causes Of
earthquakes with electrical phenomena.
The great earthquake OF Lisbon in 1855 led
Rev. John Mitchell, professor Of mineralogy
at Cambridge, to examine the subject, and
in 1760 he published in the Philosophical
Transactions o remarkable essay on "The
Cause and Phenomena OF Earthquakes"
Regarding the earth as having liquid
interior, covered by comparatively thlr
crust, he conceived that wages might b,
generated In this subterranean liquid, anC
that such waves, by shaking the fexibl,
crust, would produce 'the shocks Of al
earthquake. His illustration Of the move
ment Of the ground is that Of a loose car
pet, thrown into undulations by beiuI
shaken at one corner. This theory doe
not appear to differ much from that whicl
was yesterday expressed by Maj. Powell, o
the geological survey, gentleman who's
authority upon this matter may be consld
cred almost final, until, at least, science
receives further information.
Rudler goes on TO say that, although
Mitchell's hypothesis is still accepted In
modified form by some geologists, 1t SHOULD
be remembered that many arguments o
considerable weight have been waged b,
modern physicists against the doctrine Of
liquid nucleus and thin crust, Whateve
the merits OF Mitchell's theory, he failed h
understand the true nature OF wave me
tion and the way in which 1t is transmtte,
during an earthquake shock Modern seis
mOlogiStS Geliere that an earthquake is a vi
JrdtOry motion, propagated through The soli
materials Of tie earth much IN the same tOa
/ that sound is propdgatcd by UiJrdtionS IN III
atmosphere. The development @
this view, said to have been first suggeste
by DR.. Thomas Young in 1907, especially /
It's quantitative results, lies at the very bas
s Of selsmology.
In 1915 Mr.. Mallet communicated to tn
t Royal Irish Academy his first paper o
"1hc Dynamics Of Earthquakes;n and in til
< following year Mr.. Hopkins, Of Can
bridge, presented to the British Associ
!, tion valuable report, in which earthquali
' phenomena are discussed In some detail
q Since that date the great advances In EN-
+ land have been made by DR.. Mallet, a
= sisted by the Rev. Samuel Haughton,
L Trinity College, Dublin.
Our author feels compelled to state
1 this point that, notwithstanding all that HI
D been written, little is known about u
= origin OF earthquakes. Mr.. Powlett ScroI
was led to refer most earthquakes to ii
L "snap and jar occasioned by the sudden an
s violent rupture OF solid rock-masses, au
perhaps the instantaneous injection int
them OF intumescent molten matter fro
beneath
lie believed that the rupture OF the rOcl
3 was due to expansion Of deeply-seate
!. masses Of mineral matter, consequent eth,
,f upon increased or diminished temperatur
, Mr.. Mallet argues, however, that such fra
y lures could produce only very weak IN
IS pulses, but he believed that some cart
II qmkes, Especially those marked by lon
continued tremors, may be due to Il
: movement and crushing of rock masses
; pressure produced by secular cooling
! l.. 4
IS tie agent with sesmologists, since 1t
y clearly competent to produce great effec
IS by its sudden generation or condensation
j. After all, the origin of earthquakes, SAL
d Mr.. Rudler, is probably to be regarded {