The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1903-06-14
Establishment Of chronological Sta
tions and What They Hope TO
Accomplish.
NEW, DELICATE INSTRUMENT
ONE EARTHQUAKE ALREADY MEAS
URED AND ACCURATELY TIMED.
Time May Come when the Approach
of Seismic Disturbances Can
BE Foretold.

Correspondence OF the Indianapolis Journal.
WASHINGTON, June 11.-An earthquake
survey on a grand scale is the latest scien-
tific enterprise of the government Traps
are TO be set for seismic disturbances in all
corners of our vastly scattered domain. A
brand new one has been set UP in Washing
ton, another at Honolulu. Others to be
presently installed at the governments new
magnetic observatories at Cheltenham. Nd:
Baldwin. Kan; Vieques Island. Porto Rico.
and Sitka, Alaska.
AT Philadelphia, Baltimore and Manila
are three private stations, which will CO.
operate with these six in the official chain.
The Quaker City's station is at Swarthmore
College; that of the Monumental City at
Johns Hopkins University. where IL is in
charge of Prof. II. F. Reid, the leading
American authority on earthquake phenom-
ena. The Manila station is in charge OF
Father Algue, a Jesuit scientist of the Ma
Mia Observatory. At Toronto and Victoria,
b. c., are two stations under the meteoro-
logical establishment of Canada, which will
cooperate. Others at Mexico City. Cordoba,
in Argentina, and Arequpa. In Peru. also
will contribute information. Thus not only
our insular possessions. but our continental
area and its surroundings will be very well
covered, and If mother earth sets up any
quaking within our boundaries we shall
know of it.
Earthquake traps of an entirely new pat
tern have been selected for the government
stations. One of these is already doing
work in a dark. subterranean dungeon un-
der the national Weather Bureau. where IL
caught a seismic disturbance a few weeks
ago. Another is being tested in the base
ment Of the Coast and Geodetic Survey.
whence it is to be shipped to Porto Rico in
a week or two. There IL will watch the
troubled earth crust of the Antilles. in
whose chain Mount Pelee and her consort
wrought such wholesale slaughter a year
ago.
The new instrument adopted by the gov
eminent is regarded as the most perfect OF
its kind. II is a modification of the one per-
fected by Professor Omori. secretary of the
earthquake investigation committee OF
Japan. Japan is the great earthquake coun-
try, and has gone so far as to found a chair
of siesmology-the science of earthquakes
in the University of Toxic.
THE EARTHQUAKE TRAP.
This new trap consists of a heavy weight
so suspended i'm front of tall iron pedestal
as to be always in neutral equilibrium and
unaffected by any influence other than
gravity. While the earth ~ quaking direct
ly below it it is standing still for the mo-
ment. 1t is spanned by an iron arch. whose
base Is a stone pier penetrating into the
earth. Earth movements are directly COM
municated to the arch. Hence. when even
the slightest earth tremor takes place the
arch moves Herewith and the weight below
remains quiet suggested. Attached to
the stationary weight, by a jeweled pivot.
is a long. slender arm OF aluminium. with a
writing pen as its outer end Upon the
same foundation with the arch, and sharing
all earth movements with IT. is a revolving
wheel whose tire is Of paper. The writing
pen rests against this paper. The principle
of the instrument in a nutshell is that
earthquakes move the paper against the pen
and record the earth's tremors I'm zigzags
or curves But by delicate adjustment OF
the aluminium arm IL is made to exaggerate
the earthquakes tremor to a measurable
degree The wheel with its paper tire makes
one revolution every hour. The writing pen
starts its record on one edge. and by means
of thread on the wheels axle is made
gradually to trace a spiral over the paper.
unless an earthquake interrupts IL. Thus
the normal lines of the pen do not overlap.
By means Of an electro-magnet attached
to a specially made clock current Is COM
municated every minute to another pen
point. The latter gives jerk when IL re-
ceives the current and thus checks of min
utes along the spiral line traced by the first
pen mentioned. A new paper tire is put on
the instrument at the same minute each
day. Thus, knowing when a new record Is
set, the exact time OF a zigzag earthquake
record can be determined by counting the
minute marks on the paper.
A pair of these instruments is neces-
sary for each station. One. always pointed
north and south. records earthquake vibra-
tons moving east and west: the other, d.
rected east and west, records north ard
south vibrations. An earthquake will make
a record on both instruments at once.
The zigzags will differ, but the two paper
records will be taken from the wheels ard
delicately compared with scale. The ex-
act direction OF the earthquake and the
width of its horizontal waves can thus be
estimated TO nicely.
ONE QUAKE LATELY TRAPPED.
The earthquake trapped by this new
seismograph at the weather bureau was
unnoticed by the public 1t was not report
ed in the newspapers. and would never
have been discovered IL this part or the
world had not an instrument as delicate
as this been in place. The seismograph
was installed in the latter part of Febru-
airy. 1t replaced a more crude instrument
which for several years had been set TO
record merely the time OF the beginning
OF local earthquake shocks. The new In
strument imported from Strasburg. Ger
many. had been In place about a fortnight.
when. on the morning Of March Is. IL re-
corded a zigzag. perfectly inscribed and
showing all OF the recognized characters
istics OF earthquake phenomena. The curve
shows that there were preliminary trem-
ors, commencing at s:29 a. m. and last
ing five minutes The main tremors then
succeeded for two minutes and thirty-six
seconds. The terminal tremors lasted for
twenty-six minutes and twenty-four Sec
onds afterwards The total disturbances
lasted thirty-fo-ir minutes At its greatest
height the earth beneath the instruments
moved a trifie over hundredth OF an inch
from side TO side. No wonder the public
xas nm ware NJ fhe shock