The Ketchum keystone. [volume] (Ketchum, Idaho) 1885-1899, 1893-10-28
GREATEST OF LIGHTS.
The Mighty Searcher Now In Use
at Chicago.
Tho Reflected Beam Cast by the Mann
moth Lantern Equal to Millions
Upon Millions OF
Candles.

moth Lantern EQu11 60 muAAo0e
Upon Millions OF
Candles.
To America belongs the honor OF con-
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 ventilator on
the top of the drum, and the total
weight is about 5000 pounds, but SO
perfectly is it mounted and balanced
that a child can move it in any di-
rection.
The rejecting lens mirror used IN
this protector is $50 centimeters, or 90
inches in diameter. It is concave
spherical mirror Of the .Mangin type,
Tree from spherical alteration, reflect
ing sensibly parallel beam of light.
It was manufactured especially for this
protector in Paris, France, and IS
most perfect specimen of optical work,
three and one-fourth inches thick at
the edges and one-sixteenth 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
1000 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 fve-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.
It is entirely automatic in its 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 one-halt
inches in diameter and twenty-five
and one-half inches long, with five
sixteenth of an inch core of soft carbon
running from end to end through It's
center. The lower or negative carbon
is one and one-fourth inches in diane
ter, is fifteen inches long and also has
a core of soft carbon running through
It's center. In addition its outer sur
face is heavily coated with copper.
The positive carbon is set little In
front of the negative, and thus almost
ali the intense light of the incandes-
cent crater is cast upon the reflector.
The maximum current at which this
lamp operates is 200 amperes, and at
this current the lamp has luminous
intensity of about 10000 to loo, 900 can
dies, the reflected beam total lumin-
Gus intensity of about 375,OO0, 900 can
dies, an intensity which the eye cannot
appreciate. In looking at the side OF
the beam the spectator only distin-
guishes stream Of light Of compare
lively low intensity, but in looking at
the beam directly its brilliancy is full
ly seen and the effect is absolutely
binding Ventilators at the top and
sides allow a constant current of all
to pass through the drums and dlssl
pate the heat generated by the arc
lamp, and they nre SO arranged tha'
| 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 colored glass the
operation of the lamp may be watched
and its adjustments verified.
It was observed that the space with
in the beam was violently agitated
and closer observation revealed thu
| fact that millions of moths and minute
insects were lowering in it. attracted
bv the brilliancy Of the light. Mex
morning bushels Of dead moths, beetles
| other insects and some small birds
were swept up from the roof OF
which the protector stood. They hat
been killed by the intensity OF tn
light.
How far the powerful beam Of Ggh
Of this instrument can be seen is dit
fcult to state. The search light set VI
on Mount Washington. in the Whit
mountains, has a diameter of onl..
thirty inches, and reflected ligh
from the mirror of about 100, 900 candl
power, yet the newspaper can be rea'
in its beam ten miles away, and tn
light can be seen from points 100 mile
away. How much farther then could thi
375, ,000, 900 candle power light be see'
in a clear atmosphere, free fror
moisture, If the protector could b
mounted upon an eminence sufficient
| high to clear all obstacles.