SCIENCE BEHIND THE GUN.

Auckland Star, Volume L, Issue 187, 8 August 1919, Page 8

SCIENCE BEHIND THE GUN.

VALUABLE WORK ON WESTERN FRONT. SPOTTING ENEMY LOCATIONS. (By Telegraph.—Special to "Star.") WELLINGTON", Thursday. Further light on the highly-developed scientific information organisation among the Allies waa given members ot the Wellington Philosophical Society by Major E. Marsden, M.C, Professor of Piiyeica, who lectured on "Guni Location on the Western Front." Major Marsden, who was specially engaged on gun location work on the Western front for a considerable period, said that the field surveying companies in France, which located the German guns by flash-spotting and sound-ranging, had done very excellent work. They were handicapped greatly at first by having heavy and inadequate maps, but theso were rapidly improved. On Sth August, 1918, when the Canadian and Australian Corps delivered their great attack, only one German gun was able to reply, owing to the excellence of the maps that had been prepared and th<4 manner in which the German guns had been previously spotted. The result was that the British casualties were very small. The maps prepared ■were solely for the use of the artillery and surveying, and in consequence liaafto be very accurate, especially for the -twelve-inch British railway guns. lii the case ot Big Bertha, which bombarded Paris, tho Germans, he understood, had to make a half-mile correction in order to allow for the rotation of the earth during tho period the projectile was undergoing its 70-mile flight. (Laughter.) The Germans ultimately discovered the triangular method of flash-spotting, which, by comparison of distances, enabled them to locate the exact position of a gun. The British soon followed the example set, and as usual defeated the Germans at their own game. Another valuable method adopted 'was that ot air-burst ranging, in which the height or | burets was specially observed and deductions worked out therefrom. Soundranging, a specially valuable method, was carried out by means of microphones- registering the time of the receipt of the sound on two instruments, which registered at the same time. They could get direct bearings on the gun that wae firing , , and when the sound arrived later on one instrument than on another they could tell the angle from which the gun was fired. The microphones were worked in paire with striking results.

All guns gave two sounds, the first crack of the shell as it passed through the air, then the gun wave. Both were registered by the microphone. Other instruments gave prompt photographic records, with the result that within four minutes of the receipt of the sound the position of a gun could be spotted. A battery taken on by sound could be settled very quickly. In one month early in 1918 the Germans on the Western front lost as high as 13 per cent, of their total guns through counter-battery work.