Arizona republican., 1920-12-11
LISTENING DEVICE ID FO|L SUBMARINE
 EDISON INVENTION

never made public, Now, however, the part American ingenuity, and particu- larly Mir. Edison. played in winning the war has been disclosed in a his- tory of the naval consulting board is- sued by Secretary of the Navy Dan- iels
 The volume reveals achievements which, if projected decade ago, Rrob- ably would have been ridiculed as visionary" Chief among these was Q device by which the launching of a torpedo could be heard on shipboard 1000 yards away-or further than torpedo can be effectively launched from a submarine.
 This invention was but one of a score or more contributed by Thomas A, Edison. president of the board.
 MT. Edison appears to have been the moving spirit of the board. For saking his laboratories at the out break of the war. he practically became a. naval officer. He spent most of his time in the navy department of fices here. and took long deep sea cruises that he might be in closer touch with the problems to be solved.
 Because of the German submarine menace. ship protection claimed most of the attention of the board. To this problem Mr. Edison devoted his tra- ditional 24 working days. and after overcoming many obstacles finally perfected his listening device.
 This contrivance was in the form of an outrigger suspended from the bowspFit of a vessel and containing an immense photograph diaphragm. By means of compensators, the noise of the vessels engines was obliterated, thus making it possible for the device to work perfectly even when the ship was blowing at full speed through the toughest seas.
 With this device boats moving 1,70o yards away could be readily heard, while the vessel was going full speed A submarine bell five and one-haIi miles away could also be heard while a 1 big storm was in progress and tae ! boat also proceeding at full speed. Mir. Edison followed this invention l with a device for the quick turning l of a vessel whenever the detector iu- ! dicated that a torpedo was coming iu | the vessels direction. He did this by | means of strong conical canvas bags | A heavy rope was attached to the | mouth of the bag. and light rope 1 in a slip knot. to the tapering end. When cast into the sea the mouth l opened. filling the bag with water l and thus acting as drag. By pulling | the lighter rope the small end of the | bag was opened. This let the water | out. instantly relieving the resistance | Four of these bags cast from the side of a 5000 ton vessel laden with 4,00s tons of coal caused 1t to turn 90 de- 1 grees from her course in two minutes with an advance of only 200 feet. Night sailing of ships next attract ed his attention. By working day ana night over the records of submarin' sinkings he discovered that not nor, than per cent. of the sinkings tool place at night.
 MT. Edison Commenced to work ou his plans for the ships to sail in ant out of the danger zone at night; t forsake the old standard lines o travel as much as possible; to ancho through the day in comparativel' shallow waters and harbors wher submarines could not approach them steaming only at night to other port of anchorage on the way to their des tinations.
 MT. Edison prepared a new set O strategic maps on which he charte, the harbors in which there was saf anchorage for long distance inshor in comparatively shallow, but saf waters. where submarines could no approach submerged.
 Other wartime inventions by Nil Edison were a cartridge for takin soundings; a convoy light visible t all the vessels in the convoy, but in visible from the decks of a submarine an underwater searchlight capable C s throwing rays 200 feet; a projectil z that would enter the water from a \ angle instead of richocheting: a sta bilizer for submerged submarine and time fuse to cause shrapnel burst only six feet above the groun He devised g. mask to protect oE H servers on the tops of masts fro1
 smokestack gas, turbine head fC projectiles which enabled the Iatt,
 to be fired from smooth bore guT
 and still have rotation and accuracy H drew up plans for mining Zeebrugs
 harhor. and developed a method [
 which communicating signals betwee = warships could be sent by means - mirrors.
 - Mir. Edison devoted q great deal Il thought to various plans for preven
 Ing sinkings, and he suggested a nun
 Der of schemes to this end One
 these was proposition to furnf:
 merchant ships with a type of sp
 cially designed three inch shells fill,
 with an oleum smoke producing con
 pound with which to blind submarin
 if they had long range guns.
 The problem of extinguishinc fir
 in coal bunkers he solved with a sm;
 stream of silicate of soda played on
 coal or wood fire. The moment f
 silicate strikes the incandescent bo
 the small quantity of water in t
 silicate evaporates, and the glowil
 body becomes coated with a glas
 surface, excluding the oxygen and e
 tinguishing the fire.
 The study of a direction finder f
 hostile airDlanes was undertaken
 determine the direction of a plane [
 fore it was visible, by determining {
 direction of the source of the sou
 given off by it's engines. This is h.
 1t was done:
 Two horns at & fixed angle to (
 another conveyed the sound to (
 posite sides of the same diaphra)
 and swung the horn system. both
 horizontal and vertical planes. UT
 there was no movement of the q
 phragm, because the sounds convel
 by both horns were of equal value 2
 therefore neuralized one another.
 It was found very difficult to
 zero readings, but with some train