The Seattle post-intelligencer. [volume] (Seattle, Wash. Terr. [Wash.]) 1888-1914, 1893-01-22

\ AL loco, Wtfc VI
daily occurrence in the neighboring viii
lage of SummerviIie, and after the fatal
shock the tremors and accompanying de-
tonations--likened unto 'the booming of
siege guns" by war survivors-continued
for months. even if they may yet be said
70 have ceased entirely; and the far
reaching New Madrid earthquake of ISL
the greatest of American earthquakes
was followed by a diminishing series OF
seismic vibrations. lasting over two years
and, according to the testimony of inhab-
itants, reappearing at intervals ever since.
Yet howsoever numerous the premonitory
tremors and howsoever extended the Pc
Rod of diminished vibration, each disturb
ance is an independent shock coming
without warning. ending without notice.
By reason Of the appalling character of
| the earthquake shock. as we'll as by reason
Of its unex pected coming and rapid going.
| the phenomena of earthquakes long re-
NAMED mysterious, their laws long euded
human ken it is only within the last half
| century. indeed, that seismology-the sci
| ence of earthquakes-grew into being.
/ And so immature was this branch of
| knowledge even during the last decade
| that its sum was doubled through study of
| the last great American earthquake. by
| which Charleston WAS devastated and 100
lives destroyed six years ago. Not yet
| may the science be considered as fully de-
| veloped but enough has been ascertained
! 10 indicate how the earthquake acts and
where it is TO be feared, as well as TO sug-
gest why il occurs and how its dread effects
| may be avoided or diminished.
The earth beneath our feet is made up
not OF absolutely rigid but yielding mate
| rails, in which electric pulsations or vibra-
tons may be and indeed are continually
| developed and transmitted. Just such
| elastic vibrations as those constituting the
earthquakes may be felt by one who stands
upon beam of wood or iron when IT is
struck heavy blow. The effect of the
blow Is 10 produce a complex series of
| VIBRATIONS. differing greatly IN period and
| amplitude: some of these V brations are
| sonorous, and sound is produced the
pitch and timbre Of which are determined
by the constitution of the beam; these
vibrations run the length of the beam and
| are communicated to the air with great
| rapldity; the same or other quick-travel-
| Ing pulsations produce a singing or tin
Eting sensation in the feet resting on the
beam and finally there come the great
| vibrations of the beam en- masse by which
II may perhaps be displaced or overturned
| OF Its supports The pulsations or vibra-
| lions In the beam may be felt and, IN SIM
| PIE cases, may be analyzed with high de-
| freo OF precision; but the vibrations IN the
| sar'h are exceedingly complex, and more
| over, when the area affected is consider
sole, they interfere with each other and
develop secondary and tertiary vibrations
| W sncn an extent that the pulsations are
| beyond the reach of analysis except in
4 TIE most general terms The yfhrR-
ZION produced by rapidly mov-
| ,he locomotive IS Neritable
bus miniature earthquake; the quick
spasHa istt "hen the quarryman puts off
| shot, 10y which perhaps balanced blocks
| OF stone are set 10 rocking, or even over
turned, differs only in degree and not at
III IN kind from the great tremor that
ras cities; the srtltciai explosion at
S"ooa rock, New YORK harbor O few wears
go developed s considerable earthquake
snose vibrations were recorded by seis.
eers scores OF miles away IN differ
eht directions; and within a few months
managing earthquake extensively re-
soraed IN the daily press was few hours
thoase. po"Nei
TOR aforementioned centuries earth
tyuaAes we're simply feared as the most
ieal!a 4! seourge of mankind; Tor few
1eatuTies they were recorded and studied
it desultory fashion through the havoc
5hey had wrought; Tor few decades .hev
feSSs been investigated in more systematic
asaion' and q variety OF apparatus has
ven devised for measuring the tremors Of
1shach they consist. The simplest appara-
As Is the seism0sCope. OF which there are
tnShy patterns, all based on the principle
~ inertia IN virtue of which bodies resting
Sapon sad not connected with the earth
- 20 remain stationary rather than par
So Oh sudden movements OF the earth
l1.Ass' primitive form Is Simply bowl
~ mercury resting on a tablet or pillar
l.Aed N TIE earth, u hen the tremor comes
&she tablet and BOW ara. tisDIsced with -
EssFtn. white the mercury. partially re-
"iained by insertia. Sp.as4es over the side