The Anaconda standard. [volume] (Anaconda, Mont.) 1889-1970, 1898-07-21
GREAT ~SEARCHliGHT.
The Most Powerful One i'm the World at
san Francisco.


The government has recently secured
the most powerful electric searchlight in
the world and has placed ii at the en-
trance TO San Francisco bay to be used i'm
the protection of our Western outpost in
case of possible attack. The wisdom of
this action on the part of the government
will be conceded in view of the possibility
of International complications resulting
from the war. The light from this great
protector is conservatively calculated to
be equal to that of not less than So, 900, 900
candles. The distance from which it can
be seen is considerably more than 100
miles and moving objects can be detected
by it's light almost as far as marine
glasses can carry.
Some idea of the size of this search
light may be gained by the comparison
shown i'm this Illustration. 1t stands 10
feet 6 inches high to the top of the drum,
and the total weigh is about GOO pounds,
but so perfectly is il mounted and bal
anced that "A child can move ii in any
direction. 1t was built by the General
Electric company of Schenectady.
The rejecting mirror used is a conCave
spherical mirror five feet i'm diameter. re-
fleCting a parallel beam of light. 1t was
manufactured especially for this protector
and Is a specimen of perfect optical work.
ga inches thick at the edges and l-l6th of
an inch thick at the center. II weighs
about 500 pounds. The metal ring iTwhich
IL is mounted weighs about $50 pounds.
This great mirror is mounted at one end
of the big drum. the outer end of which
is furnished with a a door consisting of a
number of plate glass strips. Inside the
drum, and sliding upon ways arranged on
the bottom, is placed the electric are
lamp, the source of the light, which Is re-
Elected by the mirror. II is entirely auto
matte i'm its action, is six feet high and
weighs about 400 pounds. The carbons
used are also made especially for il. The
nm ar nnGitfAa carbon is H. inches
i'm diamete and 22l2 inches long. The low
err, or negative carbon, is Ia inches in di-
ameter and Is inches long. The outer sur
faces of the carbons are heavily coated
with carbon. The positive carbon is set
a little i'm front of the negative, and thus
almost all the intense light of the incan-
descent crater of the arc is cast upon the
reflector.
At the maximum current at which this
lamp operates il has a luminous intensity
Of about % 1000 to 100, 600 candles, the re-
hected beam a total luminous intensity of
about 375. 900. 900 candles. an intensity
which the eye cannot appreciate. In look
ing at the side of the beam the spectator
only distinguishes a stream of light OF
comparatively low intensity, but in look
ing at the beam directly the effect is abso-
lutely binding. Nentilators at the top
and sides allow a constant current of air
to pass through the drum and dissipate
the heat generated by the arc lamp and
they are SO arranged thar no light can
escape through them TO confuse the opera
or. All the connections for adjusting the
positions of the carbons and the lamp
are brought through the drum to the out
side, and are arranged in close proximity
to one another at one side so that all
may he manipulated by the operator
without moving from his position.
Through openings i'm the drum covered
by densely colored glass the operation of
the lamp may he watched and its adjust
ments made. The drum Is supported in
bearings at the top of a Y-shaped fork
set in "A base plate. running on small
wheels. forming a turntable. resting upon
"A massive pedestal supporting the whole
structure. The drum. fork ana base
plates are rotated horizontally on the
turntahie either by hand or by mechan-
ism. The drum may also be elevated or
depressed vertically.
For the past two years this great light
has shone over the waters of the PACING
from the top Of Mount Lowe From the
top of the mountain the great white
beam Of light has shot forth into the OBJ
security of the night and slowly swept
the country side for miles around. bring
ing every object upon which IL was dl-
rectcd into brilliant and direct relei. IL
has Illuminated the roofs of distant VII
lagos and scared their inhabitants. and
lighted up the sign boards miles away,
so that they could be easily read by
means % a glass. The PROTECTOR was fire.
quently turned towards the SKY. ana the
beam, like a supernatural finger, mas
written words upon the clouds.
Its use will now be less peaceful. In the
hands Of skilled men on the fortifications
IL Will continually sweep at night the wa
tiers adjacent to San Francisco, revealing
any suspected boat or vessel that an en-
envy might send to attack us from that
side.