The daily morning journal and courier. [volume] (New Haven, Conn.) 1894-1907, 1897-09-29
THE TALL MONUMENT WAGS
ITS LOFTY CAPSTONE CIRCLLNG
ABOUND IN SPACE.

1t Has Done So Ever Since the Shaft Was
Finished and 1t Always WiIl-The Move
ment Recorded Three Times IA Day-Due
to Winds and Storms and to Expansion
and Contraction.
1t is not generally known that the
Washington Monument, which, to most
people, is symbolIcal of stability and
immutability, shifts out of the perpen-
dicular nearly every day. In fact, this
gigantic pile of stone, that has for so
many years been the most conspicuous
landmark of the capital on entering the
city, rarely occupies the same position
twice on two consecutive days. For
eight years, in fact, ever since the mon
ument has been completed, scientific
readings have been taken three times
day to determine how much out of the
perpendicular the monument has de-
flected. From these readings 1t is APP
parent that now, and for many years
past, the Washington Monument has
had it's capstone circling around in
space anywhere from one to four inch
es from where it ought to be.
Let no one imagine from this fact of
the monument getting a move on it
self that there is any danger of the big
shaft topping over, 1t is on too firm a
foundation for that The early con-
structors Of the monument, when it was
commenced back in the forties, did not
build upon the shifting sands. AL
though the site selected was at that
time marshy and on the banks of the
peared insecure, they protited by les
son from the Bible, and first laid firm
foundation. So firm, indeed, is this
that it can be stated almost with GER
tainty that the variation of the monu-
ment is not due in any manner to an
imperfect foundation. Scientists do not
always agree as to the real reason of
the monuments variation but it is
generally conceded by many of them
that 1t is due to the winds and to con-
traction and expansion of the stone due
to the heat of the sun
That there are many prevalent theo-
rles as to the cause of the variation, a
reporter who set out last week to OBJ
serve the phenomena soon discovered
In the course of one afternoon various
theories were advanced that it was due
to the heat expansion caused by the
sun, to the winds, to the movement of
the earth, to imperceptible earthquake
shocks, to magnetism, and to an erro-
neous Indicator which failed to register
correctly, Several persons even de-
clared~ that in spite of science they did
not believe the monument moved at all
1t is much easier to prove that the
monument does move than to find out
why 1t moves. There is an appara tus
in the monument now, which was
placed there by General Casey, under
whose. direction the monument was
completed, while he was at the head of
the engineer corps of the army This
consists of very delicate pendulum,
the slightest vibra ton of which is re-
corded by two telescopes With hair-line
perpendiculars in them, This pendu-
lum is suspended in a protecting cylin-
der of sheet iron, which excludes all ex-
ternal forces which might affect the
stability of the pendulum. The pendu-
lum proper is a heavy brass weight
weighing perhaps twenty pounds. and it
is suspended by a brass wire which is
attached to level iron eirder exactly
one hundred and seventy-four feet
aboye the level of the floor Of the mon
ument. This point, one hundred and
seVenty-four feet up, is at the center of
gravity of the marble shaft That is. if
ii We're possible to suspend such a gi-
gantic mass of marble from one single
point, where the weight would be equal
ly distributed. that point would be
found where the wire of the pendulum
commences.
1t is easier to understand when it is
explained that of the 81. 720 tons which
are Incorporated in the monument ex-
actly one-half of the weight is above
this point and the other half below If
this center Of gravity should ever get
outside of the base of support-that is,
the square foundation of the monument
the shaft would fall over For in
that the center of the monument at
this one hundred and seyenty-four foot
level We're three feet out of plumb and
yet remain stable, but in order for the
monument to fall the center of gravity
would have to move something over fif-
teen feet. AS a matter of fact, the cen
ter of gravity rarely moves over an
inch and a fraction, so that the danger
of the monument ever falling is COM
paratively insignificant
However. General Casey thought that
it would be wise to detect the first indi-
cation of a variation as soon as it hap
pened. and he therefore introduced the
pendulum. Although protected from
wind and other influences by this cylin-
der the brass weight is suspended in a,
small bucket of water, in order that it
might be free from unnecessary sway
ing and still free to indicate a move
ment. On a support above the level of
the water are placed two telescopes at
right angles to each other Both have
the hair line perpendiculars found in
all surveyors telescopes, and both are
adjusted so that the pendulum wire will
drop accurately between these perpen-
diculars The telescopes can be moved
so as to get in line with the pendulum
whenever it moves. Indicators on the
telescopes show how much out of plumb
the pendulum is One of these indica-
tors detects the north and south move
ment and the other the east and west
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