New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1898-05-22
SHARPSHOOTING AT SEA.
HOW ACCURACY OF GUN FIRING IS SECURED
RY THE Use OF THE RANGE FINDER

by THE USE OF Ilif' l.fN'I' i''N''~
From Tho Scientific American.
The accuracy of modern rned guns is one OF
the wonders OF engineering TWO eNperne''t,a az
shots fired a few years ago at the same ee-
Walton from the same gun fell Within thirty
yards Of each other. after traversns distance
OF twelve miles. If modern rife IS lain upon
the target. with proper elevation ana t''"" v,
arcc for windage il Is safe 10 say the shot VIII
find the mark The correct elevation or me
gun cen only he determined II the distance Oh
the target is known. and the exact ue.eia". y
nation f the distance # a moving object Is Il
problem that has worried the gunner ever since
the dag when round shot was hrst thrown
from the sides OF the wooden iightlng SNIP
In the early days the determination OF the
range was "A matter Of Cucsswork. Inc gunner
assumed distance elevated ms gun ACCORD
ingly and watched the course az the SHOT II
~ fcll short he increased the elevation, ana II
II passed over he decreased it. This was all
very well in day when the guns were 100
feeble to do much execution except Ak ci"st RANK
and few dozen shot thrown away mao" niue
impression upon a ships magazines win the
advent If modern ordnance. however. Win the
sixty-ton guns and costly charges. IN" necessity
~ accurate fire became imperative, ana ord
nance experts set about dcvising some sci"ntitc
method Of finding the range AT sea The earliest
and best known device Of the Kind was the IN
ventiDn Of Lieutenant Fiske. Of tn" United
States Navy which has been installed on many
81 our ships. and Is widely in use in the various
nayics ~ the world
The Fiske rang. finder is based upon the we'll
known principles 81 ldIt survey INK WIN Al'
transit and engineers chain II surveying
party come TO a broad river Whose width has 10
he determined "A base line IL measured along the
bank and the angles which this line makes with
n mark on the opposite bank are measured 10y
tn. transit Then knowing the length of the
base line am. the two angles. the distance across
tn. river can be determined 10y trigonOmetry.
Applying this To- ne range finder. a base line
- car.fullv measured between two points near
opposite ends II the ship. and over each point
"A range finder. answering to III" engineer
transit is permanently set w. II the tcle-
scopes 81 The two finders are simultaneously
conycrCcG upon the same point on "A distant
object (ship. fortress cityD the observers viii
be- In possession II the trgonomctricai data
necessary 20 compute the distance, namely, the
base and the two has. angles.
In the din. hurry and slaughter ~ sea fight.
however. % would b" din cult 10 max" tn" n"ccs-
sarv calculations. rs no distance between III"
ships. and therefore. the observed angles. keep
changing and in order to max" the dct"riui-
nation of tho distance automatic. Lieutenant
Fi-hc placed his t"les, opo In the circuit II
Whcafetono bridge and caus"i their change Of
position to record me distance f the object
IN. graduated scale Of delicate galvanometer.
All that was now necessary FOR the OBJ
servers at the two range finders 10 keep the
crosshairs f the telescope upon the same point
Of the ship. and the electric current translated.
were. the angles into distances ana
corded them los the movements OF "A needle over
an arc graduated into hundreds and thousands
II yards one Of these galyanOmetcrs is placed
I'm the coming tower and one at each OF the
principal gun stations.