The times., 1899-08-06
TO STUDY THE MONUMENT
Co,onel Bingham's Plans for In
stalling Scientific Instruments.
A fantogrnph Arrangement to Make
Continuous StaticnI Record OF
the Huge shaft and seismoEraph
to Chronicle the vibrations of the
Earth-The Record by IA PIummet.

Col Theodore A. Bingham, the officer in
charge of the public buildings and grounds
in the District of Columbia. is absent from
his office on leave. but it was stated at the
War Department this afternoon that di-
rectly after his return to this city he viii
press the proposition looking 10 the install
lasion in the Washington Monument Of q
pantograph and seismograph Combined
with the pantograph there are TO be eontin-
uous thermometric readings at the base
and top. the outside and inside OF the great
obelisk.
The statical records OF the Monument
are quite interesting. but it is the opinion
of Colonel Bingham that in order TO know
what is taking place in the Monument the
record of the piummet should be c0ntinu-
Gus. The present plummet by which the
stability OF the shaft is registered. consists
OF copper wire three-sixty- -fourths OF an
inch in diameter suspended from the hori-
zontal plane containing the centre CT grav-
ity of the Monument. which is at height
OF Ia feet. 10 1-2 inches above the doorsill
OF the Monument The top of this wire is
attached to an adjustable brass screw, fas-
tened into the underside of a north and
south I-beam at point about ten feet
west of the west wall of the Monument
AT the bottom the wire is attached TO
another adjustable screw fastened to a
twenty-five pound brass plamb bob. The
bob Is suspended in a bucket of water
to prevent movement from ordinary yibra-
ton. The wire itself is protected from
top to bottom by u casing OF galvanized
iron pipe. fastened at top to the underside
of the I-beam above referred to. and Sc
cured to the diagonal braces of the stair
way by circular bands of iron. Near the
floor this pipe expands into a hood and is
connected to the pIummet-house (which is
also Of galvanized iron) by riyeting and
soldering. In the interior OF the
plummet- is a hollow iron ped
estal bolted TO the floor. with a two
inch circular opening on top for the free
passage OF the plumb wire. On the east
side of the pedestal is a door which
gives access TO the interior. in which
stands the bucket of water containing the
plumb bob"
On top OF the pedestal are two telescopes.
one on the north side facing south and cne
on the east side facing west The tele-
scopes are moved by micrometer screws
which cause them TO travel, the north one
along an east and west graduated scale,
the east one along north and south
graduated scale. The readings of the north
instrument increase to the west; of the
East instrument 10 the SOUTH 4uc scales
are graduated TO inches and tWenIieths of
an inch and BY means OF a micrometer
graduated into fifty sections, twenty
threads to the inch may be read TO thou
sandths of an inch. Variations in the po-
stions of the plummet line are determin-
ed by variations in the readings of the
scales when the plummet line comedies
with the centre vertical wires of both tele-
scopes.
Colonel Bingham has said that it is OF
little value to know what she readings OF
this plummet are at the same hour OF
each day. but that if the travel OF the
plummet were known during the hours
Of sunlight and during the hours Of dark
ness. the ereord would at once become of
high scientific value The readings now
aiken each day are plotted for each month
on a scale 100 times greater than reality.
but, owing to the lack OF continuity. these
olottings are still merely tests OF stability
1t is the opinion OF Colonel Bingham
hat il would be quite possible TO construct
1 photograph, enlarging 100 times, at
-ached to the piummet wire and resting on
| horizontal table covered with paper,
which would give a continuous record of
he movements OF the plummet, this aper
% be moved along the table By means OF
'ollers actuated by clockwork- Ii is said
hat the record thus obtained would be OF
great value if combined with thermome-
er readings at the top and bottom of the
shaft. As the temperatures differ on all
our sides of the Monument, il is thought
hat it will be necessary TO have these
eadings made on all sides. and both in
Iide and outside
seismograph will be installed for the
purpose of recording the vibrations Of the
arth.