The Banner-Democrat. [volume] (Lake Providence, East Carroll Parish, La.) 1892-current, 1898-07-23
AIMING Big GUNS.
INGENIOUS RANGE.FINDERS MAKE THEM
EFFECTIVE At LONG DISTANCE.

The rif1ing of guns and conseQuen
greater accuracy and longer range Civ
en- to modern projectiles has made !
possible to lombard an enemy from
much greater distance than couft
formerly be done. AS a result Of thi
1t has become necessary to have som'
instrument with which to determine &C
curately the distance of the object O
attack in order that the gun may re-
ceive the elevation called for by It ant
thereby the form Of the curve to be
traversed.
Range finders, as such instruments
are called, are, for the most part
founded on trigonometry. though some
are based on the velocity of sound as
transmitted by the air. These, how
ever. are no longer used, for tactical
reasons. The first range finders in
vented were small and simple, and
could be easily moved from place to
place. The knowledge Of a base line
was necessary to their use either from
the butt of the instrument when 1t
was directed to the extreme ends of
some object. the size of which was
known, or from some point of observa-
ton where base line could be meas
ured. AS the range and accuracy of
I further increased these irstru-
ments were found to be too imperfect
for the requirements.
| The chief imperfection Of earlier
range finders was that as the instru-
ments were adjusted simply by the eye
they could not be directed with enough
accuracy. They were usually held in
the hand of the operator and therefore
were not sufficiently firm. Modern
range finders are equipped with an adj
justing telescope and are placed on a
stationary stand, from which measure
ments are taken. The ideal range
finder to fulfil all demands made upon,
1t would have to have absolute accur-
acy in regard to all ranges and be en-
tirely independent of the physical adj
vantage or disadvantage Of the place
where it is to be used.
Such an instrument is, however, at
present unknown. and triangulation is
the only means used to find the range
of a target. The range finders now in
use at the Notifications that defend the
entrances of the important harbors of
our seaboard are based on trigono-
metric principles and are of two kinds.
The more simple and easily operated
of these is placed in tower or on an
elevation near the battery whose fire
1t Is to direct.
The adjusting telescope is then d.
rected at some object whose distance
Is known; from this point the tele-
scope is then turned toward the object |
whose range Is to be determined, and |
the angle between the two is recorded |
BY means Of this angle and the base
line. or known distance from the in
strument to the object at which it Is |
at first directed. the distance to the |
second object is determined. The first |
object is usually anchored in waters |
adjacent to the battery in order to |
avoid any error that would arise from |
the rise and fall of the tide If 1t were
situated on shore. Only one operator
is necessary to use this range finder.
The principle of the other range
finder Is much the same, but two oper-
ators are necessary and telegraphic
communication between them and the
battery is indispensable. The opera
tors are placed at certain known dis
lance from each other with their in
struments and adjusting telescopes.
Each keeps his telescope pointed at an
vessel. The angles made
by an imaginary line between the two
observers and imaginary lines extend
Ing from them to the vessel is thus
constantly recorded. A side and the
two adjacent angles of a triangle
whose vertex Is the vessel being thus
known, it is only necessary to solve
the triangle to determine accurately
The vessels distance.
The angles are telegraphed stimuli
saneously from the operators to the Of
6cer who directs the fire of the guns. /,
Ind they in turn, determine the range ,
and instruct the gunners how to aim
heir guns. The officer in command
If battery is somewhat handicapped :.
n directing the accurate aiming of I,
lis guns by the natural error of the /.
'uns and by varying atmospheric and /.
weather. conditions. The powder charge
u gun, though Of correct weight and
lenstty, may not be of normal strength
md the muzzle velocity of the projec-
lie may be affected.
Variations in the density of the at S
nosphere alter the resistance to the l
'assage of the projectile, and thus af- 9
ect its range. Wind also affects both S
he range and direction Of the projec-
lie. The range table of gun Is there
ore prepared from the result of ex- n
erimental practice and corrected to n
mean height of barometer and Their Ii,
nometer and a mean density of atmos- a
here. Allowance Is also made for /,
ny wind variation. As the larger a
uns at our Notifications can only beI i
,aded and fired at intervals of three !,
linutes, and as the object Of their i
re would, as rule, be constantly !,
hanging its position, there would be :
tile to be gained by experimental fir :
,g. :
II, however. shot that has been cor
sctly aimed by means of the ranke
nders should fall short of the mark
,r some of the above reasons, the N
ext gun would be slightly elevated. n
hen II itsovershot the mark third Y
IN would be fired at mean elevation al