The Norfolk Virginian. [volume] (Norfolk, Va.) 186?-189?, 1897-10-03
The Lofty Capsione Of the Washington
Monument Circles Around In Space.
SHIFTS OUT OF POSITION EVERY DAY
IL Rns Dono 80 Ever Since tho Struc-
ture Was Finished ana Il Always
VIII = The Movement Recorded
Three Times II Fny-Due 10 Expan-
sion nnu Contraction.
Fromt the Washington Tlmes.)


Washington monument. which, to most
people. is symbolic Of stability and i'm
mutability, shift out Of the perpendIcu-
Aar nearly every day. In fact, this gi-
gantio 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 monument
has been completed, scientific readings
have been taken three times a day to
determine how much out OF the perpen-
dicular the monument has detected.
From these readings 1t ia apparent that
now, and for many years past, the
Washington Monument has had its cap
stone circling around in space anywhere
from one to four inches from where It
ought to be.
Let no one imagine from this fact OF
the monument getting "a, move on itself
that there is any danger OF the big shaft
topping over. 1t Is on too firm u foun-
dalton for that. The early constructors
Of the monument, when 1t was COM
menced back In the forties did not build
upon the shifting sands. Although tho
site selected was at that time marshy
and on the banks Of the placid Potomac
and might have appeared insecure; they
proflted by n lesson from the Bible and
first laid firm foundation. So firm, In
deed, Is this that 1t can be stated almost
with certainty that the variation of the
monument Is not due in any manner
to an imperfect foundation. Scientists
do not always agree as to the real rea-
son Of the monuments variation, but 1t
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.
Thof Nor oInnk
rles as to the cause OF the variation, q
reporter who set out last week TO OBJ
serve the phenomena soon discovered.
In the course of one afternoon many
theories were advanced that IS was due
to the heat expansion caused by the
sun, to the winds, to the movement Of
the earth, to the imperceptible earth
quake Shocks to magnetism and to an
erroneous indicator which failed to
register correctly. Several persons de-
clared that even in spite Of science they
did not believe the monument moved
at all.
It is much easier to prove that the
monument does not move than to find
out why it moves. There Is an appar-
atus In the monument now. which was
placed there by Gen. Casey, under whose
direction the monument was completed.
while he was at the head Of the cngi-
neer corps OF the army. This consists
OF q very delicate pendulum. the slight
est vibration OF which Is recorded by two
telescopes with hair-llne perpindiculars
to them. This pendulum is suspended
in n protecting cylinder Of sheet iron.
which excludes all external forces
which might affect the stability
of the pendulum. The pendulum
proper Is heavy brass weight
weighing perhaps twenty pounds,
and 1t Is suspended by n brass
wire which Is attached TO a level iron
girder exactly ia feet above the level
OF the floor Of the monument, This
point, ia feet up. Is at the center Of
gravity OF the marble shaft. That IL,
II 1t were possible to suspend such n
gigantic mass OF marble from one SIN
gle point. where the weight would be
equally distributed, that point would be
found where the wire OF the pendulum
commences
It ie easier to understand when 1t Is
explained that Of the Sl,I20 tons which
are incorporated In the monument ex-
act1y one-half Of the weight is above
this point and the other half below. If
this center OF gravity should ever get
outside Of tho base of support-that Is,
that square foundation of the monu-
ment-tbe shaft would fall over. For
instance. the shaft might lean over SO
that the center of the monument at this
174-foot level were three feet out of
plumb, and yet remain stable, but In or
der for the monument to fall the gravity
would have to move something over flf
teen feet, the center Of gravity rarely
moves over an inch and n fraction, 80
that the danger OF the monuments ever
falling Is comparatively insignificant.
However, Gen. Casey Thought 1t would
be wise to detect the first indication Of
variation as soon as 1t hanppened.
and ne therefore introduced the pcndu-
1um. Although protected from wind
and other influences by this cylinder the
brass weight Is suspended in a small
bucket Of water, In order that It might
be free from unnecessary swaying and
6tfll free 10 Indicate a movement On n
support above the level of the water are
placed two telescopes at right angles to
each other. Both have the hair-line per-
pendlculars found in all surveyors tel
escopes, and both are suspended that
the pendulum wire Will drop accurately
between these pcrpendiculars. The tel
esoopes can be moved so as to get I'm
line with the pendulum whenever It
moves. Indicators on the telescopes
show how much out OF plumb the pen
dulum Is. One of these indicator de-
tects the north and south movement and
the other the east and west vibration.
AS the center Of gravity is but ia
feet above the level or a trifle over one
third Of the entire height it follows that
the top stone OF the monument moves
over three times the distance covered
by the center Of gravity. To be exact,
whatever the center Of gravity is out
OF the perpendicular should be multi