The herald., 1893-08-27
THE LARGEST IN THE WORLD,
An Electric Search Light That
Is Immense.
1t Is Now Being Put Up at the
Worlds Fair.
It's Dimensions and tho Peculiar Feat
ures OF It's Construction-The
Tremendous Power OF
the Affair.

electric search light in the world, now
being set up at the worlds fair. It
stands about 10 feet inches high to the
upper side OF the ventilator on the top
of the drum, and the total weight is
about 5000 pounds, but 80 perfectly is it
mounted and balanced that child can
move it in any direction. 1t was built
by the General Electric company. The
rejecting lens mirror used in this pro-
jector is 150 centimeters, or go inches,
in diameter. 1t is q concave spherical
mirror of the Mangin type, free from
spherical alteration, rejecting a sensi-
bl7 parallel beam of light. 1t was man.
in Paris, France, and is a most perfect
specimen of optical work, 81 inches
thick at the edges and 1-16 OF an inch
thick at the center, and weighs about
500 pounds. The metal ring in which
it is mounted weighs about 750 pounds,
and the total lens, ring and cover weigh
about 1900 pounds. This great mirror is
mounted at one end of the big drum,
the outer end of which is furnished
with door consisting OF metal rim in
which are fixed number of plate glass
strips 5-16 of an inch thick by
5 inches wide. Inside this drum and
sliding upon ways arranged on the bot
tom, 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 feet high and weighs
about 400 pounds. The carbons used
are also made especially for it. The
upper.or positive carbon ia \ inches in
diameter and 221a inches long. with q
5-16 of an inch core of soft carbon run
ming from end to end through its center.
The lower or negative carbon is IL
inches in diameter. is Is inches long and
also has core of soft carbon running
through its center. In addition its outer
surface is heavily coated with copper.
The positive carbon is set a little in
front of the negative, and thus almost
all of the intense light of the incandes-
cent crater is cast upon the reflector.
The maximum current at which this
this current the lamp has luminous
candles, the reflected beam total
candles, an intensity which the eye can
HOV 0PStCCAUbOs LA lOOhinA au biO p1OO
of the beam the spectator only distin-
lively low intensity, but in looking at
the beam directly its brilliancy is
fully seen and the effect is absolutely
binding. ysntila.ors at the top and
sides allow constant current OF air to
pass through the drum and diesipate the
heat generated by the arc lamp; and
they are 80 arranged that no light can
escape through them. All the copnec-
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
manipulated by the operator without
moving from his position. Through
openings in the drum covered by densely
colored glass the operation OF the lamp
may be watched, and its adjustments
verified. The drum ia supported by
trunions in bearings at the top of Y.
shaped fork, set in base plate, and the
whole is supported on system of fric-
tion wheels, forming turntable resting
upon tho top of massive pedestal sup
porting the whole structure. The drum,
fork and base plate may be rotated hori-
zontally on the turntable, either by
hand or by gearing provided for this
purpose. The drum may also be ele-
waited or depressed in vertical plane by
similar gearing.
Before the protector was sent to the
worlds fair, public test was made at
Conn. From the roof of
the works the great white heam of light
shot forth into the obscurity of the
night, and slowly sweptthe countryside
for miles around, bringing every object
upon which it was directed into brilliant
and distinct relief. 1t illuminated the
roofs of distant villages and scared their
inhabitants. and lighted up the sign
boards miles away, 30 that they could
easily be read by means of glass. The
protector was turned upward towards
The sky, and the beam, like q super-nat-
lral divine finger, wrote words upon the
of light to the starry
1t was a majestic mani
of mans invasion CT the realm
of Phoebus.
1t was observed that the space within
The beam was violently agitated, and
closer observation revealed the fact that
millions of moths and minute insects
we're lowering in it, attracted by the
of the light. Next morning
bushels OF dead moths, beetles, other
insects. and some small birds, were
swept up from the roof on which the
protector stood. They had been killed
oy the intensity of the light.
How far the powerful beam of light of
his instrument can be seen is difficult
o state. The search light set up by
he same company on Mount Washing
on in the White Mountains. has a
liameter of only 30 inches, and re-
lected light from the mirror of about
90, 900 candle power, yet the newspaper
AN be read in its beam ten miles away,
md the light can be seen from points
90 miles away. How much farther,
hen. could this S75,000.000 candle
'ower light be seen in a. clear atmos-
here free from moisture, If the pro-
ector could be mounted upon an emil
ence sufficiently high to clear all sur
ounding obstacles
Worlds Fair Columbian Edition Illus
trated Herald.
This beautiful publication, printed on
be finest book paper, is now on sale by
II the newedealers and at the HERALD
usiness office. 1t contains 48 pages of
lformation about Southern California
nd over so illustrations. AS publica-
f~s- l. L