The Birmingham age-herald., 1921-05-06
PROTECTION AGAINST
 TORPEDOES

our capital ships are being built SD that one torpedo will not disable then and 1t might take two or three +o sinJ them. This method may, in time be adapted to transports and all large yes- sels used in war service
 The development of devices for de- teeting submarines; of the radio com pass. which tells a ship it's nositio,, a f sea; of the monricochet shell, which is not deflected when 1t hits the wafer. of small cannon for aeroplanes: of star shells that are a great aid in night firing, throwing a blaze of light over enemy vessels while not revealing the positions of our own ships-these arc only few of the inventions that came out of the war. Beginning as a cruda affair, carrying 50 pounds of explosive the depth charge was developed into a huge bomb, carrying 600 pounds of INT, timed to explode at any dentb- n reliable weapon that was the terror of the U-boats
 The paravane, an English invention proved of the greatest value in protect ing ships from mines. Like two hupe wings spread out in the water, it picked up mines, and its wires bore them away from the ships where they could be ex- ploded without danger to the vessel Mines played big part in naval war rare The Germans sowed the seas with them, and if the allied mine sweeners had not been so energetic and skiIlful in removing them, they might have been as destructive to shipping as the U-boats were. The new mine our navy developed in 1917 was regarded as de- cldediy superior to any of it's predeces- sors, and this was the type used in inc North sea mine barrage, so per cent or which was composed of American mines. laid by American vessels.
 DETECT APPROACH OF "SUB"
 At last, after considerable experiment American genius devised q "listenine" apparatus that would disclose the pres- ence of submarine miles away. if if was in motion. It enabled the opera tors, by the sound of the propellers and other noises, to tell whether the shin heard was liner, a warship, or a "s1b ;, rms was the most efficient device of the kind perfected during the war, and was adopted by other nations.
 Better guns for airplanes was a vital need. Our ordnance officers vastly inn proved the machine guns in use But for anti-submarine warfare we needed large calibre gun with sufficient power to penetrate the hull plating of the U-boat, and the Davis nonrecoil gun was produced. This is a radical departure from previous types, the bar rel being open at both ends, and loaded at the center by rotating half of the barrel around an offset axis
 The projectile leaves the front barrel in the usual way, while a rear charge of equal weight is projected from the rear barrel. Consequently no recoil force is transmitted to the mount. A Lewis machine gun is mounted above the Davis gun barrel, so that, in aim ing, the machine guns bullets are fired in approaching the target, and the Davis gun shell speeds forth as the mark is reached.
 SMOKE BOXES" BY THOUSAND
 Decided improvements were made in range finding and fire control devices, increasing the efficiency of large and medium calibre guns Smoke boxes" were manufactured by the thousands. and placed aboard merchant as well as