New-York tribune. [volume] (New York [N.Y.]) 1866-1924, 1890-01-20
A NEW RANGE-FINDER.
THE NEW CRUISER BALTIMORE TO HAVE IT.
WORKED BY ELECTRICITY-ITs ADVANTAGES
OVER OLD METHODS.

OVER OLD METHODS.
There will be shipped from this city this afternoon
TO the new cruiser Baltimore, at Norfolk one Of the
most valuable electrical inventions ever applied to
vessel Ii is called the ran ge finder, and was
devised and perfected by Lieutenant Bradley A.
Fiske, of the Navy, who made and applied to tho
cruiser Atlanta an electrical apparatus for hosting
ammunition. This machine Lieutenant Fske
has been at work upon for several weeks in room
on the ninth floor Of a building at Greenwich and
Thamesst., to which could only be obtained
by special courtesy, and after passing through
labyrinth Of Railways and rooms filed with machinery
and instruments and drawings.
The new mechanism is intended for finding tho
range and position of distant object with greater
facility and accuracy than by the old method Of tri
anguations with the seXtant or by theodoltes The
machines mounted upon two stout tripods fastened
to the Deck and consist principally OF two telescopes,
each Of which is mounted upon circular plate that
has its graduated scales its electric wires ETC. The
method Of finding the range of any distant object
consists in first determining fractional part OF
conducting body bearing in length ratio to tho
angle included between two lines Of sight directed
upon that object, and measuring the electrical ro-
sstance of the part found At each Of these telc-
scopes at opposite ends OF the baselne, is an OBJ
server who takes observations Of the distant object,
movable or immovable A third observer is stationed
at galvanometer, who adjusts the contacbar to tho
resistance wire at the receiving instrument, which,
through electrical resistance points at the correct
distance Of the object. If the observers at the tce-
scopes keep the officer at the chart receiving in
strument constantly advised to how their tee-
scopes are pointing the exact distance Of the OBJ
ject is known at each second OF time. The instru-
ment recently tried I'm getting the distances OF
ferry boats and other vessels moving up and down
the river and not only there difficulty in
reporting the range continuously but careful COM
putations made afterward proved that the average
the long base-llne was only iAtenths OF
per cent. This > "A smaller than 10 made by
tneOIOltes any other instruments.
The invention i especially applicable 10 use al
connection with pneumatic guns Tor the projection
OF shells charged with high explosives. a gun OF
this type IS placed In the bow Of vessel az certain
liked elevation, and the range OF the pr0lectle j.
regulated by varying the air supply admitted 10 inc
gun. IL thus becomes highly important 10 determine
the distance Of the target with all possible accuracy
The two telescopes may be mounted on opposite
sides of the vessels upper deck her breadth OF beam.
for example, being the known b3Se-lne, while tho
ealvanOmetcr may be placed below and convenient TO
the air regulating valve of the gun The Observers
on the upper deck train their telescopes on the OBJ
ject and the observer AZ the gavanOmetcr determines
the distance in the manner already described, AMI
in accordance with tins determination adjusts tho
valve
Il has also been proven that BY the use OF this
mechanism guns may be trained and tired at an OBJ
ject. even when the smoke at the guns Is 50 dense
that OF the guns see tie object 10 be
did know its distance direction. have been en-
abed by the commands given 10 them 10y the Observers
the position finder to put al per cent OF the shots
into the deck of an imaginary iron lad AZ ranges
from 5000 TO 1000 yards. The guns OF tort
could also be fired with close accuracy by an ohlcer
distant from the smoke. noise and confusion OF the
battery. The instrument is also valuable IN deter
mining distances Of points Of land or c0astline.