The record-union., 1898-07-11
SHOOTING BIG GUNS.
THE GUNNER MUST BE EDU-
GATED TO THE WORK.
Must be Able to Do Logarithms Un-
der Fire to Work the
Range Finder.

Dis Ic pdlltu one VI lliG IIIooSl hloAoAOl
guns in place at Fort Hamilton.
''Well, if your ordinary enlisted man
can think I could with a few days
training, of course" replied the civilian
who had been favored with view of
the new ordnance.
THAT is one of the most modest
speeches I've heard" was the ironical
rejonder. 1--WE spent four years at
West Point, two at the artillery school
at Fort Monroe and l was just congrat-
ulating myself on my being finally well
prepared for this emergency. And yet
my nervous system hasn't been tried
and may jumble my logarithms when
I'm under fire"
The civilian started. What are you
talkin about?'
Firing these guns. Did you suppose
we sighted along the top the way Long
Tom Coffin used to do in Cooper's story
and, pulling lanyard, landed our shot
ten miles away just on the point where
we wanted it to go? That was the old
way, but to-day more science is re-
quired and we can tell to an inch where
the projectile we fire will strike:
NO CHILD'S PLAY.
"But it is no childs play, you may be
sure, and not only one gunner must be
steady, but every man who has any
thing to do with the transmission or
computation of information connected
with the laying Cor sighting) of that
gun has to be absolutely steady, prompt
and reliable. If you will just imagine
how much of an error surveyor would
make if he ran a line eight miles long,
having set his bearing one minute right
Iof%
what must be accomplished in the lay
ing of our modern ordnance.
I'm the days of the civil war ranges
were so very short that the gunner
had no difficulty in seeing his target
and laying his gun directly upon It.
Wind and speed of target cut no figure,
because the projectile had such short
distance to pass over that neither had
enough time to act to make any appre-
ciable difference. But now, when firing
at target eight miles away, all of
these things make themselves felt.
There is the rifling in the bore, which
gives the projectile the rotation neces-
sary to keep it from tumbling, and
which will in our service carry the pro-
jectile to the right. The direction
and force of the wind the direction and
speed of target, the temperature and
barometric pressure of the air, which
affect the resistance of the air to pass
| age of the projectile. All these things
! have to be taken into account, and
they each vary under all sorts of con-
ditions, so that they can only be figured
| out for each particular shot at the time
| the gun is fired. But they are not
such difficult problems to the officer,
who lives in an atmosphere Of such
things.
Most of this information must be
worked out from data obtained from
| firing tests, and must be thoroughly
assimilated by the expert artillerist.
| Then by taking observations at the
time of firing, data is obtained from
which results can be computed
''The most important part Of the op-
Grafton is, of course, to locate
the target. The invention which
has enabled us to do this is something
wholly Americana development of our
regular army, which in certain locali-
ties it is so much the fashion these
days to run down.
This invention is the range finder.
1t looks a simple affair. A tall modern
tower with a substantial foundation,
built on a commanding hight, and con-
nected with the guns-perhaps half
mile distant-by telephone. At the top
is large telescope, adjusted on a pol
ished steel circular table. A dial on.
the telescope frame is eogged with the
edge Of the circular table, and gives
at any instant the direct reading in
azmuth. Another dial is so arranged
that elevation or depression of the tele--
scope gives its. indicator a correspond
I,;@ ,e Il 1a o,.fJi-
nary transit fitted to read vertical an
giles But in this case, Instead of read
ing anglesrof depression, distances are
indicated in yards to the point where
the line of sight pierees the water. An
adjustment corrects for hight. Of tide.
QUICK WORK, THIS.
"It is only necessary, then, to point
our telescope at the water line Of the
ship and read directly azimuth and dis
tance. These are rapidly transmitted
by telephone to the guns and plotted
on a piece Of drawing paper. Three of
these observations. twenty seconds
apart, are plotted, and the gun has to
be fired eighty seconds after the last
observation is taken, or at the end of
| two minutes total time. We have the
| location of the target at three differ
| ent times. It is now necessary to COM
| pute where 1t will be at the end of the
| eighty seconds.
| = "A vessel running twelve knots an
| hour will pass over 1,2OO feet in one
minute or 1000 feet in eighty seconds,
so that If we fired at the point where
| she was at the last observation we
might miss her 1,6OO feet or some frac-
| ton of that depending on her direction
of sailing with reference to us. If we
| fired point blank-i. e., aiming right at
| her-we would miss as much as she
would pass over in the time Of flight
of the projectile. This, for ten thous-
and yard range, might be twenty Sec
| onds.
1--WE have now the positions of the
| target at a given future instant, but
| 1t is referred to the position of the
range tower. We must now correct
our data to refer to the guns position.
Then we are ready to make corrections
for drift due to rif1ing, effect of wind,
condition of atmosphere and abnormal
powder and projectile. The gun is laid
with the resulting data by means of
| degrees and minutes marked on the
traverse circle Of the gun platform and
elevation arc on the side of the ear
riage, and we are ready to fire. It is
necessary to allow time-called time of
fiight'-for the projectile to reach the
target at the end of eighty seconds, so
the guns must be fired that long ahead
of time. - II .-~--z+~--se
ALL A QUESTION OF SCIENCE.