Daily independent. [volume] (Elko, Nev.) 188?-1915, 1893-10-10
GREATEST OF LIGHTS.
The Mighty Searcher Now IN Use
at Chicago.
The Reflected Beam Cast by the Mann
moth Lantern Equal to Millions
Upon Millions of
Candles.

structing the largest and most power
full electric search light in the world,
now being set up at the worlds fair.
1t stands about ten feet six inches high
to the upper side of the vcntilator on
the top of the drum, and the total
weight is about 5000 pounds, but SO
perfectly is it mounted and balanced
that child can move it in any di
rection.
The rejecting lens mirror used in
this protector is $50 centimeters, or 60
inches in diameter. 1t is a concave
spherical mirror of the Mangin type,
free from spherical alteration, reflect
ing scnsibly parallel beam of light.
1t was manufactured especially for this
protector in Paris, France, and is IL
most perfect specimen of optical work,
three and one-fourth inches thick At
the edges and onc-sixtcenth of an inch
thick at the center, and weighs about
500 pounds.
The metal ring in which it is mount
ed weighs about $50 pounds, and the
total lens, ring and cover weigh about
1.GOO pounds. This great mirror is
mounted at one end of the big drum,
the outer end of which is furnished
in which arc fixed number Of plate
glass strips fvc-siXtcenths 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 carbonS used are also
made especially for it. The upper or
positive carbon is one and onc-half
inches in diameter and twenty-five
and ore-half inches long. with q five
sixteenth of an inch core OF soft carbon
running from end to end through its
center. The lower OF negative carbon
is one ard onc-fourth inches in diane
ter, is fifteen inches long and also has
q core OF soft carbon running through
its center. In addition it's outer sur
face is heavily coated with copper.
| The positive carbon is set q little in
front of the negative, and thus almost
all the intense light of the incandcs-
cent crater is cast upon the reflector.
The maximum current at which this
lamp operates is 200 ampcres, and at
this current the lamp has a luminous
! intensity of about 90, COO to 100. 900 can
| dies, the reflected beam a total lumin-
| ons intensity of about 3T5, GOO, 600 can
dies, an intensity which the eye cannot
appreciate. In looking at the side of
| the beam the spectator only distin-
cuisines a stream of light Of compare
| lively low intensity, but in looking at
the beam directly it's brilliancy is full
lv seen and the effect is absolutely
| binding. Ventilators at the top and
! sides allow q constant current of air
| to pass through the drums and dissi-
| pate the heat generated by the arc
lamp, and they are so arranged that
no light can escape through them.
All the connections 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 po-
sition. Through openings in the drum
| covered by densely eolored glass the
| operation of the lamp may be watched
and it's adjustments verified.
1t was observed that the space with
| in the beam was violently agitated,
and closer observation revealed the
fact that millions of moths and minnie
insects were lowering in it, attracted
by the brilliancy 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 by the intensity of the
light.
How far the powerful beam of light
of this instrument can be seen is diff
flcult to state. The search light set up
on Mount Washington, in the White
mountains, has q diameter of only
thirty inches, and - reflected light
from the mirror OF about 100000 candle
power, yet the newspaper can be read
in its beam ten miles away, and Che