Evening star., 1898-12-14
other movements east and west of

| and the other movements east and west of
| the zero line.
| 1t would be possible to get. upon a sta
| tionary paper. by the same means an exact
enlarged record of the movement of the
plummet for each day, starting from a
| point as zero, but the movements are so
| minute that record thus obtained even
though enlarged 100 times, would be very
| difficult to study.
1t would cost between $500 and 5000 to
! construct one of the Instruments required
| for this work, but the result would be very
| interesting and valuable.
The record thus obtained would lead to
| immediate valuable results if combined
with thermometer readings at top and bot
tom of the monument. As the tempera-
| lures differ greatly on the four sides of the
monument and rom outside to inside it
would be necessary to ave thermometers
on the four sides of the monument both
outside and inside. Then again these rec
ords should be continuous and thermome-
terS giving such records are on the market
Thus we would have continuous heat
record from the rising of the sun to it's set
ting. on all sides of the monument from
the top to bottom, and also during the cool
ing hours of the night, and this. compared
with the continuous travel record of the
plummet. would tell US exactly what the
monument was doing all the time and
would give an fsight into what some
scientists call the breathing movement of
the monument.
1t might also prove valuable to have a
SelSmograph at top and bottom of the
monument. to record movements due TO vi
brations of the earth. l am not at present
prepared to Sugge. I a form for a seismo-
graph, although the form used by the
weather bureau might be used until a bet
ter Is devised. borrower, it would be diff
cult to provide n foundation for such an
instrument free from oscila ton due to
other unavoidable causes.
Changes in Iron Framework
The perforated tie rods used in the con-
struction of the interior iron framework
OF the monument have for a long time past
been observed to buckle, for the most part
toward the inside, and to an extent suffi-
ciently to strike the corners of the ele-
vator cage. At first no particular atten-
ton was paid to this, further than to bend
the tie rods outward, and in some cases to
tie them out The number of buckied rods
has. however, increased with lapse of time
1t is believed that this buckiing is in the
main due to vibrations set up in the iron
framework by the rise and fan of the eie-
vator cage, which runs almost continuous
ly for eight hours daily.
An examination of the construction of
the iron framework makes it difficult to un-
derstand how these tie rods buckle,
but the fact remains; and since they do
buckle, they must be subject to strains
not contemplate in the original COnstruc-
ton, because had strains of compression
been fOreseen the tie rods would have been
replaced by compression members. The in
terror columns of the framework are PhOe
nix columns, OTdced rigldly every twenty
feet. and these twenty-foot columns are
amply strong to support any load that may
be imposed upon them in the ordinary use
of the monument. Even if possible, it is
not desirable that the elevator cage should
rise and fall in IA rigidy vertical line 1t
is held off from the guide rails by rubber
buffers, which permit ID certain iooseness of
fit. 1t was observed, however, that when
the desired rigidity was imposed on the
motion of the cage at the base of the shaft
the cage became jammed at an elevation of
about 290 to 800 feet. This led to a series
of careful measurements of the interior
iron framework from base to top.
study of these measurements shows
that there has been a certain amount of
twisting at various elevations. No move
ment in the masonry has been detected.
Caused by Enrth's Vibrations.
1t is believed that one cause Of these
movements in the monument is due to vi
brations In the earth transmitted through
the foundation. What these vibrations are
or when they occur is unknown, but the
probability of their existence is thought
to be supported by an unexplained fact,
viz on many days of perfect calm the
plumb line vibrates excessively, whereas on
days when high wind may be blowing
lilt piuiilD lhtt VIII DE dl I6St.
1t is believed that the twists can be taken
out of the iron framework by substituting
channel bars for the tie rods, and this
work has already been begun, many new
channel irons having been placed IN posi-
ticn. 1t is hoped to complete it during the
ensuing year.
1t is also prop6sed to substitute steel
springs for the rubber buffers III the rum
ming guides of the elevator cage, so as TO
prevent very largely any vibrations or
blows being caused by the motion of the
elevator cage.
The facts discussed above do not affect
the stability of the monument nor the sale
ty of the elevator, and are of Importance
solely because of the great Watchfuiness
exercised to make the use of the monu-
ment as safe human skill can make It.
| The facts are also of scientific interest.
Locating the Monument.
The original bench mark used for the
Washington monument.was the surface of
! the capstone of the Jefferson pier, No. L.
| built on the first meridian line of the
United States, established in 1913 and again
re-established in 1904 1t is at the intersec-
| tion of the center line of the north and
south basement doors of the Executive
Mansion and the center of 10th street eX-
tended due south and OF due west line
| from the center of the Capitol. 1t is 2,643
linear feet (nearly) due south on the merid
ian line from the outer side of the sill of
the basement door on the south side or the
Executive Mansion The surface OF the
ground being unfavorable, the Capitol not
being visible at the spointsof intersection,
an obelisk (No. y was planted on the
meridian line due west from the south end
OF the Capitol, where the building was dis
tinctly seen, and thence measured north
ward on the meridian line half the
| length of the Capitol Q75 feet S1a inches)
| to the point of Intersection of the meridian
| line by west line from the center of the
| Capitol.
| The above points on the meridian line
We're fixed in 1893 by two wooden posts
| driven in the ground. and permanently
| fixed in 1904 by building a stone pier in
| place of No. l. The pier was by by feet
| and covered by a sandstone cap. There is
| a receipted account for the materials and
| building this pier on file in this office, for
| the amount of s111.211a, dated December l.
| 1904 and signed by John Lenthall. who
| was at that time an assistant under Archi-
| tect Latrobe at the Capitol
There was a tradition among some old in