WINNING THE WAR

Dominion, Volume 14, Issue 81, 30 December 1920, Page 5

WINNING THE WAR

PART PLAYED BY EDISON

HOW HE TRACKED U-BOATS

Thomas Alva Edison devised 110 marvellous electric machine to ' annihilate, at one .stroke, the armies of oi\r enemies, as credulous persons expected at the outset of tho war, that lie would do. What .Edison did do, however, is set forth by a contributor to "Engineering and Contracting" (Chicago), and, after perusing the account, the reader may not be blamed for adding the name of Edison to those of the numerous persons and organisations who are credited with "winning. tl\e war," Some of Edison's contributions were:— Tha device for detecting submarines, by sound, from a moving vessel. That for turning a' ship quickly at right, angles. Collision mats'Jor minimising loss from torp;do attack. Method; of camouflaging vessels. Obstruction of torpedoes with nets. The iinder-wqter searchlight. Oleum cloud-shells. High-speed signalling with eearchfeht?. . ... Water-penetrnting projectiles. Rcscarchcs on the zigzagging of ships. Production of nitrogen gus irom the air.' A hydrogen detector for submarines. . Protection of observers from smokestack gas. Device for us; in watching for periscopes. Putting out coal-bunker fires. Direction-finder for hostile airplanes locating hidden guns by "soundranging." The preservation of submarine guns from rust. Detecting "Subs." by Sound. • submarine activity began to plav havoc tfith shipping, tho problem of "detecting the location' of submarines by sound was considered one nt '.he foremost problems of the 'lay, and in a very short time it was recognised as being, perhaps, the most difficult one. Mr. Edison gave this problem a large part of his atifention, and in the summer and fall of 1917 had reached a lair degree of success in detecting sounds of tornedoes as far as 5000 yards distant. Ho became convinced that if lio could install on a ship a device that should be arranged so that ill would always be irom 10ft to 20ft. ahead of the bow of tho vessel, and'if this device should carry a vibrating' diaphragm, it would not have tA. contend with lihe noises of the ship, itself. The device euccedea, &nd boats moving 1700 yards away could be readily heard while the vessel was going full speed. A submarine bell fivo and a half miles away, could also be heard by tho operator while a big, storm was m progress. With this device there would be no difficulty whatever in hearing a torpedo more than 4000 yards away, and this is far beyond the effective distance at which a torpedo can be launched from a submarine. The noise_ by a torpedo is Tery piercing and peculiarly distinctive.. Quick Turnings. •Mr. Edison desired to provide cargoboatß with, a. means'of turning the ship very quickly to a right-angle course on hearing the' launching of a torpedo by his listening device. His plan included the use of four seaanchors, each about 9ft. in diameter at the mouth, and each attached to a rope, jffhe plan whs to fasten the endsi of these' ropes securely in the bow of the fthip and to! have the sea-anchors placed at the end of the ropes and midway ot iSie ship. If the observer at tho listen-ing-device reported a torpedo launched by a submarine nt ft distance, the signal was given, and the four sea-anchors were to bo • immediately released and thrown overboard, and the holm thrown hard over, bringing the ship almost to a standstill, rapidly turning her at right angles in her original course. In a test a loaded vessel 325 ft. in length was turned 90deg. from her course in 2nun. lOsec., with an advance of only 200 ft. Mr. Edison, experimented on a plan to enable merchant ships to escape torpedoes by the use of ft guu, similar to a iVeiich-mortar, from' which should bo fired an obstruction netting. Tho plan was that a large number o£ these new nhould be thrown in its path, giving sufficient retardation lihat it would,be stopped or be so delayed as to miss tlio ship. One of the problems placed before Mr. Edison was to provide a searchlight to bo used under water by submarines. After making" a great, number of experiments he found thai 1 the green line of barium m tho 'arc (light) penetrated salt water farther than any other lie had observed. His last experiments wero with a 60foot tube filled with sea-water, at the end of which sufficient light was transmitted to read print. During tho height of enemy submarine activity, Mr. Edison also devised a typo of projectile which would enter tho water direct without ricochet, and would continue its course without deflection and make a penetrative hit. A simple little device for use by lookout men in watching for periscopes in bright sunlight was suggested by Mr. Edison. It consisted of a tapering metallic box, open at-both ends, fitted with * light-excluding eyepiece, and having diaphragms placed at intervals along its inside length. Tho device was painted a dead-black inside ar.d out, and its construction was very cheap. With it jects could be discerned in the full light of day that were otherwise invisible.

Locating Hidden Guns. The determination of the location of hidden guns by observing the time intervals between which the sound of.thair discharge reached several known points were early undertaken by Mr. Edison. Actual, tests made with modern guns showed that under varying weather conditions the position of :m unknown sound could be located within 2 per cent., plus or minus, of the measured distance, with' a base-line not exceeding one-sixth of the range distance. Under favourable conditions some remarkable close results were obtained. With a base-line ISflOft. long (the longest base-line used) the gun has been located over two and a half miles away, within a foot or two of the actual position. One of tho problems submitted to Mr. Edison was to find some method of preserving submarine guns from rust. He made a large number of experiments unrj Anally found that if extra fine zinc-dust is mixe<l with vaseline and smeared over the gun no rust what' ever formed, either in air, or sprayed with seawater, or wholly immersed in fresh or sea-water. If only plain vaseline was used tho polished steel became badly rusted. <