The Norfolk Virginian. [volume] (Norfolk, Va.) 186?-189?, 1897-10-03


pendulum shows that the center of grav-
lily is out of the ordinary Just one inch,
the top stone must be 3.1S9 inches out Of
where 1t ought to be. The monument
officials only trouble themselves to take
the readings Of the center of gravity,
because that Is the only important read
Ing to be taken, and the position of the
rest can be easily computed from this
fact.
MIR. John Hawkins, the custodian of
the monument, who has been in direct
charge Of the big stone pile since 1t was
completed over eight years ago, chattcd
very ertertaining'y on the subject Of the
varying alterations of his charge. Mr..
Hawkins has taken the readings Of the
Indicator each day for something over
eight years, and probably knows much
more about the variations than anyone
else connected with the monument
The variations do not get more than
three or four inches out OF the plumb
line" he said, though that Is an eX-
treme. The variations are very irreg-
ular at all times. and have not entirely
made up my mind yet as to what causes
IT, l have seen 1t stated In various
publications that it is due to the eXpan-
sion and contraction caused by the heat
OF the sun. The people who lay 1t to
this cause, however, assert that 1t moves
toward the north. because the sun is hot
test on the south. My experience of
eight years has been that the movement
moves toward the southwest. Each
month we use the daily observations to
plan out chart OF the movement, and it
Is almost invariably toward the south
west. l guess there Is not much doubt
that the sun does not have some influ-
ence on L, but ! should think that the
north side, being coolest, would con-
tract and draw the monument that way.
Instead. however, It goes toward the
southwest. I am sometimes Of the opin-
ion that 1t Is not due to the sun that
the monument moves, because, on the
hottest days, we can still read the in
dications that point toward the south.
st has also been stated that the vari-
alton Is due to winds. My experience has
been that on days when the wind was
blowing sixty miles an hour-so hard,
in fact, that you could not stand up by
yourself out there on the hill-at the
very time when you would expect the
indicator to show n great variation In
the direction in which the wind was
blowing-there would not be the least
bending in that direction. I have no.
ticed that time and again, At other
times, in dead calm 1 have been sur
prised on looking at the indicator, to
find the pendulum swaying and bobbng
around as though the monument was
~
times 1t would indicate 4 big variation.
This cannot be due to air currents within
the monument, because the pendulum is
protected by n cylinder, and the indca-
tors are protected In a closed closet. We
have lie ID the Indicators when the ele-
vator Ia running up and down, indie
the shaft. but this has never had the
slightest effect on the readings.
1T seems TO me that the variations OF
the monument must be mainly duo 10
the motion Of the earth, and slight, ir-
regular shocks would not affect n build
Ing of lower altitude. The swaying OF
| the monument, however, has brought
forth many theories. and I guess 1t Will
| be a hard matter to settle just what
| does cause It,"
Has lightning ever had any effect on
| the Shaft?" was asked.
mo. 1t has never left any effects,
| except some burned-out wires OF our
electric lights. Observations of the pen
| dulum taken after the monument has
| been struck by lightning have never
read any differently from those taken at
| other times"
| Gen John NJ. Wilson. who. in his ca
| pacity of superintendent Of public build
| inEs and grounds. has had general SUI
pervtsion of the monument for the pas;
| seven or eight wears, begged to be ex-
whatever on the variations OF the mon
ument. He said that the pendulum and
| indicators were Gen. CaSey's scheme
| and that he made 1t a point 10 never
| criticlsc anything ever done by fellow
| officer. He would only say, however,
| that the walls OF the monument We're
! eighteen feet thick. of solid stone. and
that he would leave 1t to the reporters
imagination to figure out just far such
substantial nnnld of
| pendicular.
Prof William Hardness. the superln-
tendent of the Nautical Almanac at the
Naval Observatory, gave what rs un-
douhtedly the correct eNplanat ton of the
shifting Of the stone shaft. His eXpla-
ton was that generally accepted by
scientists.
1T has been known for a number Of
years." he said. that the monument
does move. There is no doubt of that
for 1t has been proven time and again
The cause is undoubtedly the expansion
or the stones on one side due to the
heat of the sun. The sun strikes one
Side and lengthens 1t out. while the op-
poate side. being unaffected by the heat.
remain stationary. This bends the mon
ument In a slight curve. 1t does not
lean over in straight line, but bends
like a bow. If the center OF gravity
moves over n certain distance, and this
center of gravity Is but one-third of the
way up the shaft, you cannot say posi-
lively that the cap-stone moves lust
three times the distance the plumb line
Indicates. ! am inclined to think that 1.
Will move a little more than that, since
the biggest part Of the curve would be
above the center of gravity. THE exact
distance the cap-stonc does move, how
lrp ell OF