San Antonio daily light. [volume] (San Antonio, Tex.) 1886-1907, 1893-08-24
A SEARCH LIGHT

OF cOlSlIuCllh IhO i'i SoS''
most powerful electric search
light in the world, now being set
up at the Worlds fair. Some idea
of its size may be gained by the
comparison made between it and
the men of ordinary height stand
ing by it, shown in an illustration
from a photograph taken when
the search light stood on the ROOF
of the factory. 1t stands about 10
fit. 6 in. high to the upper side of
the ventilator on the top of the
drum. and the total weight is
about 5000 lbs, but so perfectly is
it mounted and balanced that a
child can move it in any direction.
1t was built by the General Elec-
trio company. The rejecting lens
mirror used in this protector is 100
centimeters. or 60 inches, in di-
ameter. 1t is'a Concave spherical
mirror of the Mangin type, free
from spherical alteration, reflect
ing a sensibly parallel beam OF
light. 1t was manufactured es-
pecially for this protector in Paris,
France, and is a most perfect spe-
cimen of optical work, three and
one-fourth inches thick at the
edges and one-siXteenth OF an men
thick at the centre, and weighs
about 500 lbs. The metal ring in
which it is mounted weighs about
75Olbs, and the total lens, ring and
cover weigh about 1000 lbs. This
great mirror is mounted at one end
of the big drum, the outer end OF
which is furnished with a door
consisting of metal rim in which
are fixed a number of plate glass
strips five-siXteenths of an inch
thick by six inches wide. Inside
this drum and sliding upon ways
arranged on the bottom, is placed
the electric lamp, the source of the
light which is reflected by the
mirror. 1t is entirely automatic in
it's action, is six feet high and
weighs about 400 pounds. The car
bons used are also made especially
for it. The upper or positive car
bon is one and One-half inches
in diameter and twenty-five and
one-half inches long, with a five
sixteenths of an inch core of soft
carbon running from end to end
through its centre. The lower or
negative carbon is one and one
fourth inches in diameter, is fifteen
inches long and also has core of
soft carbon running through its
centre. In addition its outer sur
face is heavily coated with copper.
The positive carbon is set a little
in front of the negative and thus
almost all the intense light of the
incandescant crater is cast upon
the reflector. The maximum cur
rent at which this lamp operates
is 600 amperes, and at this current
at which this lamp operates is 200
amperes, and at this current the
camp has a luminous intensity of
about 10000 to 100000 candles,
the reflected beam a tOta
luminous intensity of about 375,-
100000 candles, an intensity which
the eye cannot appreciate. In
looking at the side Of the beam the
spectator only distinguishes a
stream of light of comparatively
low intensity, but in looking at the
beam directly its brilliancy is fully
seen and the effect is absolutely
binding. Ventilators at the tops
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 that no light can escape
through them. All the cOnnec-
tions for adjusting the positions of
the carbOns and the lamp are
brought through the drum to the
outside, and are arranged in close
proximity to one another at one
side so that all may be man
ipulated by the operator with
out moving from his position.
Through opening in the drum COW
cred by densely colOred glass the
operation of the lamp may be
watched, and its adjustment veri-
fled. The drum is supported by
trunions in bearings at the top of
Y-Shaped fork, set in "a base plate,
and the whole is supported on a
system of friction wheels, forming
a turn-table resting upon the top
of a massive pedestal supporting
the whole structure. The drum
fork, and base plate may be rotated
horizontally on the turntable either
by hand or by gearing provided
for this purpose. The drum may
also be elevated or depressed in &
vertical plane by similar gearing
Before the protector was sent t
the Worlds fair, a public test wa