Evening star., 1922-11-12
STRANGE .UNDERSEA LANDS
NOW CHARTED BY RADIO
New System Proves Aid to Navigation
i by Locating Landmarks Beneath
Ocean Waves.

advisable in the interests OF the ma
tional defense. but which rebounds to
the permanent benefit of travel. in
dustry and trade. especially with re-
spect to our maritime interests.
The complete sound wave equipment
consists OF. an oscillator or sound
transmitter, sensitive hydrophone
or sound receiver and q sonic depth
finder or sound interval measuring in
strument.
Sound producing oscillators for ma
rine use are not new. as they. have
been in general use for a number OF
years. Likewise the principles OF the
hydrophone have been known for a
long time. The hydrophone was great
ly improved during the world war.
however. as a result Of developments
brought about by the then prevailing
submarine warfare.
Developments in the science OF
| sound waves nave been continued by
the Navy since the signing Of the
! armistice. and as a result hydro
| phones Of extreme sensitivity are now
| in use in our service.
The sonic rangefinder is a new in
vention of the Navy's CHIEF sound
physicist. and has been developed and
! perfected at the Navy's engineering
experimental station at the Naval
| Academy.
The functioning of the sound oscil
lator and the hydrophone was out
, lined in my article of July 2. 1922.
| The sonic depth finder is an instru-
| ment which. by proper adjustment, In
| conjunction with the known rate of
| speed OF travel of sound waves in
any medium, measures and denotes
! the equivalent of the time interval of
| travel of the sound from its source to
| a rejecting surface and the return
I Of its echo to the source. One-half of
/ this interval represents the actual
/ distance through the medium under
! consideration.
1t has been determined that sound
waves travel at the rate Of speed Of
approximately $500 feet per second
| in average sea water Gnstead Of 4.400
feet as given in my article of July
It is known that the rate OF speed
OF travel OF sound in water varies
slightly with depths or pressure and
| with temperature. Experiments are
now under way by the Navy to de-
| termine more accurately this rate OF
speed of travel in water Of varying
pressure. temperature and salinity. as
this information is desirable for more
accurately determining depths in
various waters and accurately chart
| ing the sea bottoms.
1t is possible that research work in
the science of sound waves will even
tually be prosecuted extensively by
| others for other than marine pur-
! poses.
OIL and Coal Conceivable.
BY determining its rate of speed of
travel through rock and other forma-
tions in the earth. and noting the re-
turned echoes as the waves pass from
one medium to another. II is concefv-
able that the presence of substances
such as oil. COAL etc, would be de-
noted.
In this event the great value Of the
Navy's work in sound, for other than
marine uses. would be readily ap-
parent.
A most important feature of the
Navy's new sound equipment and
methods is that the sound waves ef-
feet can be focused at any desired
angle.
The system can. therefore. be used
not only to determine depth of water.
but also to denote the presence Of iso-
lated lodges of rocks in the path Of a
vessel. partly submerged floating ice
bergs. such as destroyed the Titanic:
nearby precipitous coasts. obscured by
foes or storms. or other ohstructions
which would spell disaster to a vessel
il not avoided.
1t will be of the utmost value in
surveying routes for submarine ca
bles AS finally perfected. together
with the obtaining Of more accurate
knowledge concerning the rate of
speed of travel Of sound waves in wa
ters of various pressures and tenn
peratures, it should serve to detect
and outline the contours of sunken
vessels. such as the Lusitania, as they
rest on the ocean bottoms.
The functioning of the apparatus is
compa ratively simple. Like the radio
apparatus, it can be manipulated and
operated by the average person after