The Colorado statesman., 1913-06-21

the protection OF
that very vulnerable shaft, the Wash
ington monument. This equipment 1s
not visible to outside observers and
is rarely mentioned to sightseers, who
have probably never wondered how
great would be the fall thereof If the
monument were to be struck and dis
rupted.
At the very beginning of the con-
struction of the monument a plan for
protection was provided. The possi-
bility of its being struck In case OF
storm was obvious, 80 the protective
plan matured with the blue prints.
The four iron beams forming the
framework for the elevator shaft
which rises in the center of the monu-
ment were always, during course OF
construction, made to extend higher
than the surrounding masonry. SO that
when the shaft was left in an unfin-
ished state during the Civil war. at
the height which is indelibly marked
on the outside, the beams exceeded III
height. The purpose of this was to
have them serve doubly-that of at
tractors and conductors of the light
ming whtch would play about the mon
ument and framework for the elevator.
At the base of the beams. where they
rested on their foundation stones. cop
per wires were attached. These were
run to an underground well thirty-two
feet in depth under the shaft. This
we'll was filled with water and had
bottom of clear sand. Under this
sand ran a thin layer of water in
which was grounded a fiat copper
plate. 1t was to this plate that the
wires were attached This seemingly
intricate grounding is an illustration
of the delicacy with which the details
for the protection were worked out.
During the suspension of work this
system adequately protected the mon
ument. When the work was resumed
the beams were extended to the point
where the crowning pyramid joins the
slanting sides of the shaft. When this
pyramid was completed the most deli
cate work was at hand.
At the apex-a height of 555 feet
top of pure aluminium, then 30 ex-
pensive that 1t was worth about SIS
pound, was adjusted. From this tip
directly to the summit of each SHAFT
on the inside of the pyramid were ex-
tended and connected four copper
rods about one and one-half inches in
diameter. This connection then form
ed a complete course for the conduc-
tion of the lightning flashes in cleo
trical storms from the apex down
through the construction beams to the
inundated plate in the grounding.
The monument was finished in 1894
and the system effectively protected
until April 5, 1885. Then, during the
course of a severe storm, five i'm
mense sparks were seen to center on
and fly from the apex. but no damage
resulted. Two months later, however,
during another storm, severe dis
charge of lightning cracked a stone
under the apex and forced 1t slightly
outward. The efficacy of the system
was then questioned, and a decision
to investigate resulted in the appoint
ment of a commission composed of
Colonel Casey, United States army en-
gineer corps; Prof. Henry A. Row.
land of Johns Hopkins University and
Prof. P. c. Mendenhall of the Mas
sachusetts Institute of Technology.
These three men were about the most
prominent in the electrical world ut
that time and of all the most compe-
tent to judge and decide. They in
vestigated and concurred in the opin-
ion that the fault of the system lay not
in its insufficient carrying capacity,
but was due to a deficient number of
points of attraction
To remedy this they extended ten
rods horizontally around the pyramid.
On each Of these rods, at an interval
of five feet between, were placed
pointed conductors, gold plated and
tipped with platinum, three inches in
length. There are 200 of these con-
ductors in all, exposed on the pyra-
mid. Down the four outer edges of
the pyramid from the apex copper
wires were run. They were brought
forward toward the center to connect
with the iron beams. These four
wires, then, crossing the rods hold
ing the small pointed conductors, con-
nected them and the aluminium apex
to the beams. With the four wires
that were placed on the inside of the
pyramid as original connection, there
are now eight wires connecting POI
points with the grounding, whereas
before four wires had connected with
one point. This increase was the
remedy the commission effected.