The Grangeville globe. [volume] (Grangeville, Idaho) 1907-1922, 1915-10-21

Even with characteristic and totally
differenk sound waves available ftr
the detection of underwater craft there
stiu remained the elimination OF all
other waves by the experimenters so
that the remaining, desired sounds
would be available for the determine
ton of the distance traversed by the
waves, as well as whether or not the
submarine was Ia motion and II so In
what direction II was travelinet While
uhis may seem quite simpl problem,
1t required several months of careful
eNperimen ing and research work in de-
veloping suitable resonance tubes for
filtering out all undesirable sounds, as
well as a tinker or interrupter ar
rangement to further eliminate AL but
the desired waves. The tinker device,
Ut is explained by Dubilier. causes only
the peaks of the desired sound waves
to be heard in the telephone receivers
that are used with the apparatus. Many
electrical problems had to be solved
in connection with the tinker device
and it's circuit. among them a means
OF bringing the Interruptions In phase
with the incoming waves.
The submarine boat PLACID at the
disposal of the inventors by the French
government and used in the experiments
was detected several miles away by
using the apparatus alone. However.
1t was found advisable to increase the
range of the detector system several
fold and this was readily accomplish
ed by the introduction of a De Forest
audion amplifier between the apparatus
and the telephone receivers, ultimately
resulting in a range OF SIS miles,
The military value of the submarine
detector system now used by France
and England naturally prevents the dis
closure Of important details regarding
the apparatus and it's exact method
of operation. However. is learned
that a number OF special microphones
are lowered into the water to depth
of several fathoms at each station.
They are usually arranged in semd-
circle facing out to sea- One connec-
tion from each microphone is made to
a common wire. while the other con-
nection from each microphone is
brought to one point of a multi-con-
tact switch Each microphone is so
placed as to receive sound waves best
in one direction. Accordingly, by lis
t,ening to the sounds received by the
different microphones, slowly moving
the switch over the several contacts,
the operator can determine from the
microphone that responds the loudest
the direction of the submarine. While
the manner of denotfng the direction
In which a submarine may be travel
ing is not disclosed, 1t is safe to as
suane that this is determined by the
decreasing of the volume OF sound af-
fecting ONE transmitter and the increas-
ing of the sound volume in another,
indicating that the submarine is ieav-
ing ONE microphone zone and entering
another. The arrangements for deter
mining the distance between the shore
and the hostile submarine are not re-
veaaed The system Is not available
for use on vessels because Of its ex-
treme sensitivity
There are said to be large number
Of installations for the detection of sub
marines along the coast of England,
Scotland and Ireland, and along the
French coast bordering ON the English
channel and extending as far West as
the Bay of Biscay. These installations
or stations are spaced at suitable in
tervals and provided with means for adj
wishing fast torpedo boat destroyers and
armed motor boats of the presence OF
hostile submarines. OF the latter type
of craft 1t is reported that some 1000
are in use in the waters of the British
Isles These boats are capable Of high
speeds and are of such light draft that
torpedoes are of no avail against Them
They are sufficiently armored to with
stand the fire OF the guns carried by
the latest German submarines.