Chicago eagle. [volume] (Chicago, Ill.) 1889-19??, 1894-03-24
GIVES WARNING TO WAR sHSes.
The Hydrophone. which ReglstcrS Ne
Movements Of any Craft Mile Distant

The Hydrophone, which Registers Ne
Movements Of any Craft u Mile Distant.
Experiments are now being con.
Quoted on the perfection Of the hydro
phone, which, according to the Lon.
don Times, promises to be OF great
value in marine warfare. The prin-
cipal object Of this simple apparatus
Is to give warning to q port or fleet
Of the approach OF torpedo boat
even II the latter Is totally submerged
and, therefore, invisible. 1t consists
esscn tially Of Two rarts, one sub
merged in the sea, at a proper dis.
lance from the port or fleet to DO
warned, and at u depth sufficient to
escape the surface agitation. This
part may be described as an iron bell
jar which, on being plunged mouth
downward into the water, retains q
volume Of air in the upper portion or
bottom, where a copper box, protect
ing the sensitive organ Of the appara-
tus is fixed. The organ In question
is merely a very delicate vibratorv
contact, which makes aud breaks an
electric circuit connecting the SUBJ
merged bell with the indicator CT
second part OF the hydrophone, stu.
ated on shore or on board one Of the
ships Of the fleet. The contact 10
formed by fiat horizontal spring
fixed at one end and loaded at the
other by heavy piece OF brass, nav.
ing on its upper surface small plati-
mum stud. A fine platinum needle
kept upright by vertical guide,
rests its lower end loosely on the
platinum stud. The needle and the
stud are connected In the electric cir
cult through the guide and spring,
and When the needle dances on the
stud the circuit Is made and broken.
An clectri. current from the ship or
shore battery is always flowing
through the circuit--that Is to soy,
between the submerged bell and the
Indicator Now, the propeller Of &
torpedo boat or Of torpedo sets up
vibrations In the water, and these,
reaching the submerged bell, agitate
the trembling contact, 50 that the
needle dances on the stud and inter.
rupts the current. The conse luence
Is that the Indicator begins to work
and announces the submarine dis.
turbance. This part Of tho hydro.
phone consists essentially Of an cleo.
tro. magnet. through which the cur.
rent passes, with an arfnature free to
oscilIate when the current Is rapidly
made and broken--that Is to say,
when the current becomes intermit.
tent. The motion OF this armature
can be seen by an observer, II he
chooses to watch, but actual Observa-
ton Is not required, for the Indicator
itself gives the alarm. This taxes
place when the swing OF the arma.
ture carries 1t within the attraction
OF q magnetic contact piece fixed near
IL. The armaturc Is then drawn to
the contact piece and held fast there.
The swinging armature and the con.
tact piece are connected In Who cir.
cult Of local battery, and when they
meet the current flows to ring an
electric bell Or light an electric lamp.
The torpedo boat thus announces ito
own arrival on the scene IN spite OF
itself, and precautions can he taken
against It, Tho hydrophOne 10 Ut.
present undergoing u practical trial,
Ia England, aud Captain McEvoy,
the inventor, estimates that three Of.
the instruments suitably placedI
would be sufficient to protect Ports.
mouth harb0r. lie Is now engaged In
constructing o larger hell than that
already submerged, 10 order to meet
che requirements OF the Government
authorlt es The apparatus Is beauti.
fully worked out and comparatively
inexpensive. Moreover, II Is sum.
GENTLY sensitive to announce the
passage OF steamers mile distant
from the bell. Obviously, such IN
instrument might also be used for
submarine signaling, for u ship by
stopping and starting her propeller,
could send q message In the Morse
CODE and the shore could respond by
flashing the electric lamp. In the
case OF another ship the response
might be made by her propeller.