The Washington herald. [volume] (Washington, D.C.) 1906-1939, 1915-10-24
Detect Subs" by Sound

Writing OF tho detection OF submarines
~ sound waves tho Scientific american
lives further details of the experiments
" William Dubilier. an American cleo
ricil engineer, with numerous wireless
telephone and wireless telegraph inven-
ions 10 his credit. who recently was in
rance installing wireless telegraph APP
'aratus on aircraft. Dubilier went to
Cherbourg. on the English Channel,
Hhcre he found Prof. Tissot. of the
French .Ncademy of Science. hard at
work on a microphone detector system.
The problem of evolving a successful
system for detecting submarines by
noises peculiar to these craft was a
most difficult one. In the earlier expert
ments the French simply placed water
proof microphones below the surface.
At first the sound waves emitted by the
propellers of submarines were those
sought. but these We're found TO resemble
so closely those of other craft that they
could not be.relied upon.
Fortunately for the eXperimenters, il
was discovered that the underwater
raft were sources of sound waves of
'xceedingly high, frequency, quite dis
inctive from any other subaqueous
sounds. While the cause Of the high
pitched sound is known to the inventors,
Il cannot be divulced, since II would then
be possible for German submarine con-
structors TO eliminate the source of the
rell-tale sound waves and thus render
void the purpose OF the detector instalIs-
tons.
With characteristics sound waves avail
able, there remained the elimination Of
all other waves so that the desired
sounds would be availa Bile for determine
lion of the distance OF the submarine
and direction it was travelling. It re-
luired several months OF research work
IN developing suitable resonance tubes
Cor filterinS out all undesirable sounds
as we'll as tinker or interrupter ar
ransement which causes only the peaks
Of the desired sound waves to be heard
in the telephone receivers that are used.
The submarine boat placed at the dis
posal of the inventors by the French
government was detected several miles
away. 1t was found advisable to in
crease the range, and this was accom-
plished by the introduction of a De
Forest audion amplifier. ultimately re-
sulting in range of ffty-fve miles
The military value of the submarine
detector system now used by France and
England naturally prevents the discIos-
but IL is learned that a number Of spe-
cial microphones are lowered to a depth
of several fathoms, usually in a semi
circle facing out to sea. Each micro
phone is SO placed as to receive sound
waves best in one direction. By slowly
moving the switch over the several con-
facts the operator can determine from
the microphone that responds the loud
est the direction of the submarine. The
system is not available for use on YES
sells because Of its extreme sensitivity.
There are said to be a larger 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 stations are
provided with means for advising fast
torpedo-boat destroyers and armed motor
boats of the presence Of hostile SUBJ
marines.