The morning call., 1894-05-08
WARNING TO WARSHIPS.
The Hydrophone Registers the Move
ment of Craft a Mile Distant.
London Times

Experiments are now being conducted on the
perfection of the hydrOphOne, which promises
TO be OF great value in marine warfare. The
principal object of This simple apparatus is 10
give warning TO a port or feet OF the ap-
pToach of a torpedo-bodt. even If the latter
is totally submerged and. therefore, In
visible II consists essentially of two parts.
one submerged IN the sea at a proper
distance from the port or fleet to be warned
and at a depth sufficient 10 escape the sur
face agitation. This part may be described as
an iron bell Jar, which, on being plunged mouth
downward luto Inc wafer, retains volume OF
air In the upper portion or bottom, where cop
per box projecting he sensitive organ Of the
apparatus is fixed.
The organ IN question is merely very deli
cate vibTatory contact, which makes and
breaks an electric circuit connecting the sub
merged bell with the indicator or second part
Of the nydrophone. situated on shore or on one
of the ships OF the fleet. The contact Is formed
by fiat horizontal spring fixed at one end and
loaded AT the other by heavy piece of brass.
having on its upper surface a small platinum
stud. fine platinum needle kept upright by
a vertical guide. rests It's lower end loosely on
the platinum sTud. 1he needle and the stud
are connected in The electric circuit through
the guide and spring, and when The needle
dances on the Stud The circuit Is made and
broken.
An electric current from the ship or shore
battery is always flowing through the circuit
that is TO say, between The submerged bell and
boat or Of torpedo sets uD vibrations in the
water, and these, reaching the submerged be H.,
agiIate the trembling contact, so that the
needle dances on the stud and interrupts the
currents. The consequence is that the IDdica-
tor begins TO work ana announces the submar-
Inc disturbance. This part of the hydTophOne
consists essentially of an eectro-magnet.
through which the current passes. with an arm
ature free 10 Oscilate when the current is rap
idly made and DrOken-ihati is TO say. when The
current becomes Intermittent.
q hy
an observer, II lie chooses 10 watch, but actual
observation Is not required, for the indicator
1tself gives the alarm. This takes place when
the swing OF the aTmatuTe carries II within the
attraction OF magnetic contact piece fixed
near II. The armature Is then drawn 10 the
contact piece ana held last there. The swing
ing armature and The contact piece are con
nected IN the circuit OF local battery and when
they meet The current flows 10 ring an electric
bell or light an electric lamp. The torpedo
boat thus announces its own arrival on the scene
in spite OF Itself. and precautions can be taken
against II.
The hydropbone is ar present undergoing a
practical trial in England, and Captain McEvoy,
the inventor, estimates that three of the instrl.
ments suitably placed would he sufficient to
project Portsmouth haTbOr. He is now en-
gagged IN constructing larger bell han that
already submerged In order 10 meet the require
nenIs of the Government authorities The an
paratus is beautifully worked out and compare
lively inexpensive. Moreover, IL is sufficiently
sensitive TO announce tile passage of steam
ers a mile distant from the bell. Obviously
such an instrument might also be used cor
submarine signaling, for q ship, by stopping
and starting her propeller. could send mes
sage in the Morse code, and the shore could
respond by 3shing the electric lamp. In The
case OF another ship the response might be
made by her propeller.