The daily star-mirror. (Moscow, Idaho) 1911-1939, 1918-08-13
Allies Find Powerful and Far
Reaching Illumination an I'M
portant Factor.
USEFUL IN SPOTTING TANKS
Pick Up Hun Bombing Planes at
Distance and Keep Them Con-
stantIy in View-Equipped
With Sound Detectors.


trians were driving the Italian sol
diers from their hard-won mountain
fortresses, the defeated army had one
weapon which it constantly used to
harass and impede the foe. This was
the electric searchlight, a newcomer
on the field of battle.
Powerful lights were trained every
night upon the. advancing Austrians
whenever they came to q river cross
ing or whenever they were obliged to
halt for another reason. This ham
pered and irritated the enemy ex-
ceedingly. 1t was not only that Sc
rious danger attended any disclosure
of their operations. They suffered
also from nerves when the long feel
ers of light brushed over their faces
and hands and revealed every detail
of the work upon which they were
engaged. tE Sst7 f}f
The use of searchlights by our
own expeditiOnary forces is becoming
an important branch Of the engineer
ing service. Not long ago congress
voted an appropriation of $1,O00,0OO
for searchlights of both the field type
and the anti-aircraft type. The lights
commonly used are 36-inch lights, hav-
ing candlepower of 1,OOO,OOO,OOO, and
maximum range of approximately
10000 yards, or nearly six miles,.
First Use in Warfare.
When searchlights were first intro
duced in warfare it was expected that
they would be primarily service
able in battlefield Illumination. The
scheme was to throw light upon the
opposing battle line and show adj
vancing companies of infantry the
kind Of ground over which they had
to go. Another plan was to have
rows of searchlights parallel with the
trenches and sweep the terrain be-
fore them, lighting up the barbed-
wire entanglements laid by the foe
and exposing parties of enemy sol
diers at work repairing them. How
ever, neither Of these uses turned out
to be especially significant. The diff
ficulty was that, as soon as the lights
were in operation, they were easily
picked off by the enemy's guns. In
the same manner, they could not be
placed along the line of trenches
More recent experiments have dem
onstated that there is a real useful
ness for field searchlights. They are
now being employed to spot the en-
emy's tank advances. Instead of be-
ing hauled by horses, like the first field
searchlights, the newer ones are
mounted on motor trucks. They are
flashed for only minute or two at a
time, and are instantly shifted to an
other vantage point, This affords
them greater measure of self-pro-
lection.
The antiaircraft searchlight is the
most valuable type of light now used
by our soldiers. 1t is our most eff
fective defense against the low-fying
night-bombing plane of the Germans
Antiaircraft guns have proved almost
hopelessly inadequate in coping with
night air raids, and if it were not for
the long pointing fingers of the search
light the foe would be able to effect
some very deadly work in night at
tacks upon supply depots and ammuni-
ton dumps.
The method is to pick up hostile
bombing plane when it is about five
miles away from it's objective. 3 For
this purpose the searchlights are To-
Gated at points likely to be alta cked.
They are sunk in holes in the Hround
and are heavily sandbagged. Beth the
light and the men working it ara given
considerable protection.
Fitted With Sound Receivers.
To detect the approach of airplanes
the searchlight apparatus is furnished
with sound receivers. Without these
receivers the outfit is practically use
less The receiver can be swung
around to catch the sound vibrations,
and they are remarkably accurate in
discovering the position of the plane.
Usually it can be located within a few
degrees. The light is not turned on at
all until the airplane is practically To-
Gated. Then it is suddenly flashed on
the craft. Once bombing plane is
found it is hard for it to get away from
the inexorable pencil of light. Bomb
ing planes are not like battle planes;
they must fly in comparatively
straight lines and are not free to
twist and turn so as to wriggle out
of range of the light.
I The first thing an aviator does when
he finds himself in the spotlight Is to
rise. That is just what the operator OF
the searchlight wants him to do. The
higher he goes the less accurate his
aim becomes and the smaller grows
the chance that he can hurl MS bombs
at desired point. Furthermore, he Is
fazxled BY the light and his sense Of
security is completely destroyed. Some
times he can be Found out by one Of
the antiaircraft guns, or pursued by
one of our own airplanes. Even II the
searchlight crew does nothing more
than to brighten an airman and drive
him away it has performed defensive
act which may save quantities OF
stores and ammunition, to say nothing