The Idaho Springs siftings-news., 1915-10-08

tion in which the foe is advancing. AZ yet nohe
OF the weapons has been pointed nor. II morta1s
to be used, even been loaded.
The plotters marks upon his paper NTH point
ahead and insline with the four other dots inis
is his predicted point where the enemy Vesse.
should be a minute later. In this interval Oh
time 1t is necessary for the In the plotting
room to do a number of things necessary to make
1t possible for the weapons to score NIT. Ano
range Is not enough to know. Let us as-
sumo that the foe Is to be attacked by means OF
mortars and that the projectiles arc to soar
thousands of feet into the air upon their long
flight that may take the better part OF Two
minutes before plunging upon the vuinerao'e
decks Of the hostile dreadnaught.
It fs needful to know how long the shells Will
be in the air at that range: how far the target
will move during the flight OF the missiles; how
much the path of the projectiles Will be innu-
enced by drift due to their own rotation and the
effect of the prevailing wind the exact powder
charge that will be needed to propel the shells
this being determined by the range and the state
OF the atmosphere; and finally, how much ahead
the mortars must be aimed in order to allow for
these factors. These complications are due to
the method of indirect fire employed ana IN this
particular the mortars not so accurate as the
big rifles and. therefore,, are more d1r1cult TO
handle in order to insure good results The final
point set in the plotting room Is No g and two
minutes further along than No g. the predicted
point" the latter being verified by the angles
given by the observers at the spotter stations
when the vessel is duly reported at the proper
moment.
All of this has taken longer to describe than
actual performance calls for, because the error
factors which have been just mentioned are tabu
lated and quickly worked out graphically by
means of cunningly devised apparatus 1t must
be evident that In interval of four minutes
a big ship 1000 10000 yards off would not get
measurably closer and once the proper range is
found and the mortars loaded the shifting range
is quickly verified and the guns set accordingly
The men in the towers and those IN the plot
ting room at work all the while. At definite
intervals the instructions are sent by telephone
from the plotting room to each battery or mortar
pit and lest these vocal directions be misunder
stood the figures and orders are vtslbly repro
duced For this work the telautograph is EN-
ployed and thus words and numbers In writing
check the telephone calls.
AS has been said there four mortars in
each pit, and general thing there four
of these pits at each defense station. In other
words, a salvo OF 16 high explosive shells
be launched by indirect fire at foe II but
two of these hit the enemy she would either be
destroyed gravely damaged. because none Of
her decks would be able to withstand such
assault In practice the performances OF such q
battery have been splendid. AS matter OF rec
ord, mortar company has fired many as
ten shots in minutes 40 seconds, and in that In
tervaI made six hits while another company has
scored eight times out OF ten shots during
pro1ectiles weigh from 800 to 1000 pounds and
are charged with from 80 to 60 pounds Of high
explosive.
For the disappearing guns the modus operandi
differs in some particulars The time OF flight
OF the shot is far shorter than in the case OF the
mortar shell, the powder charge is not varied to
suit different ranges and the state Of the atmos-
phere is not deciding factor. Therefore, cor
rections are more easily made for the rife. when
1t does fire, is pointed right at It's target The
principal of the battery commander is
to know the range and this is telephoned and
reproduced by the telautograph at the firing sta
tions
The battery commander also follows the enemy
ship with telescope range finder that employs
short vertical instead of horizontal base. This
serves a check and at each gun there Is a tele-
scopic sight which Is functioned independent of
the weapon-the operator looking over the para
pet and following continually the moving quarry
By swinging his telescope horizontally he causes
the lateral angle to be indicated at the gun sta
ton below, and there the trainer swings the
weapon in unison and the elevator raises ths
muzzle agreeably to instructions from the range
finders
When the rifles have been loaded and the mo-
ment for action arrives these great war dogs
rise upon their steel launches and thrust their
muzzles above the heavy parapets of concrete
Instantly there Is thunderous boom-tbe speed-
ing projectiles their murderous mission
Before the thin veil of smoke has been swent
aside the guns have sunk behind cover and hut
for the momentary flashing OF their muzzles there
is nothing to show the spoilers on the hostile
craft where the attacking guns lie.