ENGINEERING AND SCIENCE

Dominion, Volume 13, Issue 44, 15 November 1919, Page 7

ENGINEERING AND SCIENCE

, ! NOTABLE SPEECH BY SIR CHARLES PARSONS i : SOME WAR SECRETS J The great event of I lie first day at l.ho I British Association meeting at Bourne- ; mouth (stales tho "Daily Mail") was Sir ! Charles Piiifiuns's presidential speech in 1 tho ovening, remarkable both in its mal- ' tor and in the person of the speaker, who > risked, and, indeed, at one liiuo lost, Hi? better part of his fortune on his great ■ invention, t.he turbine engine. Sir I Charles Parsons, who in his address re- | fused to touch tho subject of turbines, gave an interesting sketch of the future of engineering and' of scioucß. s Having pointed out that, with deeper ; harbours will coino ships of a thousand ■ feet and moro in length, he showed how i modom scienco and engineering enabled I ; armies unprecedented in size, efficiency, and equipmont to be drawn from ii.ll parte of tho world and to be concentrated rap- j idly in the fighting line. | Just) as tho Indian hunter puts his ear | ; to the ground to listen for'the sound of ' the footstep of his enemy, so in modern warfare science has placed in the hands , of the sailor and soldier elaborate ini Etruinente to aid tho ear in the detection , of noises transmitted, through earth, water, air, or ether. 1 . The sound-ranging apparatus developed , by Professor Bragg and his son, b.y which ; tho position of an enemy gun can be de- ' termined from electrically recorded times ! at which tho sound wave from the gun ' pusses over a number of receiving stations, hail enablod our artillery to concentrate their firo on the enemy's guns,. ; and often to destroy them. 1 Tho Frendh began experimenting in September, 11)11, with methods of locating' enemy guns by sound. The' English section began work in October, 1915, adopting the' French methods in the first ■ instance. By the end of 191G the whols front was covered, and sound-ranging began to play an important part in the location of enemy batteries. Durinjj 1917 locations by sonnd-ranging reached about 30,000 for the whole army, this number being greater than that, given by any other means of location. A single good set of observations could bo relied upon to give the position of an enemy gun to about 50 yards at 7000 yards range. It 'could also bo carried on during considerable artillory activity, Celluloid Whales. But even this was less , important .than the perfection of machines for discovering submarines and otner perils of tho.wa. After the loss of tho Titanic two patents ; were granted for tho detection of abovewater objects by their echo in the air and under-water objects by the ccho 1 transmitted through water. "Tho echo method of detection was not, however, practically, developed.', until French and English scientists, with whom was associated Professor Laugeviu, _ of tho College de-France, jealising its irnl portance tor submarine detection, brought the apparatus to a high degree df perj feotion and utility shortly before the armistice," said Sir Charles. ' Moving submarines were located by the ( pressure waves set up in the water by vibrations produced by the vessel and , her machinery. For determining direction two hydrophones coupled to two receivers, ono held to each ear, were used. But "when the vessel is in. motion or the sea is rough the water noises from the dragging of the instrument through i tho watjr and from tho waves silking the ' ship drown tho noises from tho enemy vessel, and under such conditions tho inI strum,onts are useless. "Tho assistance of eminent biologists was of invaluable help at this juncture. Experiments wero made with sea lions by Sir Richard Paget, who found that they have directional hearing under water up to speeds of six knota. Also Professor Keith explained tho construction of,tho -hearing oj'gaiw of the whale, tho ear proper being a capillary tube, too small to be capable of ji_erforming any useful function in transmitting sound to the relatively largo aural organs, which are <loep est in -the head. Tho whale, therefore, 'hears by means of tho sound waves transmitted through the substance ■ of- the head.' It was further seen thut tho organs of hearing of the wJmlo to some degree resembled the hydrophone. "Tho course now became clear. Hol- . low towing bodies in the form cf fish or porpoises were made of celluloid, varnished canvas, or very thin metal, and the hydrophone suitably fixed in the centre of tho head. Tho body is filled with wator, and the cable towing the fish contains the insulated leads to the observer on board the Vessel. When towed at some distance behind tho chasing ship disturbing noises are small, and enemy noises can be heard up to speeds of J-l knots, and at considerable distances." . "Now, with beams of 'high-frequency sound waves, it is possible to sweep the seas for the detection of- any submerged object, such as icebergs, submarines, surfaco vessels, and rocks; they may also be used to make soundings. It enables a chasing ship-to pick up and close in on a submarine situated more than a mile away." ■ Tramway Ships. Sir Charles described a "ship-leader" gear, consisting of "an insulated cable laid on the bottom of the sea, earthed at the further end; through it an alter, nating current is passed. By means of delicate devices installed in a ship she is able to follow the cable at any speed with as much precision as a railless electric omnibus can follow its trolley wire." Cables up to 50 miles long havo been used, and this device, -Sir Charles said, promises to be invaluable to ships navigating narrow and tortuous ohannels tnd entering or leaving harbours in a fog. As to aircraft development, whereas in the aeroplano tho weight per horse-power insreases with the size, with t.lio airship the advantage increases with, the size, ns in all ships. Tho larger the airship the more wind pressure she would withstand. "Tho airship appears to have a great future for special commerce where time is a dominant factor and the demand is sufficient to justify a largo airship. . . . The. only limitation in size will be tho cost. <It may'bo many years before tho airship is Increased from its present maximum of 750 ft. to 1500 ft. with success, but it will assuredly come." Sir Charles gave a rather depressed forecast of tho future of Britain. "Failing' new and unexpected discoveries in science, such as the harnessing of tho latont molecular and atomic energy in matter . . . tho great; position of England cannot bo maintained for an indefinite poriod. At: some timo moro or less remote—long before tho exhaustion of our coal—the population," he said, "will gradually migrate to those countries where the natural sources of energy (chiefly \valer-powor) arc the most abundant." Ho entered a strong plea, for his pet scheme of a. borehole, 'which could lio dug 12 miles deep at. a cast of AI.OM.OfIO-not much more than tho cost of 0110 day of (he war to Great lirilnin— • and could be extended, in granite strata to !Ki mile?. Ho suggested that;, us in Italy and in volcanic areas, "a very largo amount of power may be, in tho future, obtained directly or indirectly by boring into tho earth."