SCIENCE BEHIND THE GUN.

Taranaki Daily News, 23 August 1919, Page 9

SCIENCE BEHIND THE GUN.

! VALUABLE WORK ON WESTERN ' FRONT. SPOTTING ENEMY LOCATIONS. Further light on the highly-developed information organisation among the Allies was given 'members of

i- the Wellington l'hilosonhical Society n last week by Major E. Alarsden, M.C., 0 Professor of Physic.?, who lectured oil "finn Location on the Western Front." il | Major Marsden, who was specially ene gaged on gun location work on the Wests era front for a considerable period, said t that the Held surveying companies in t France, which located the German guns f by flash-spotting and sound-ranging, lnid ; done very excellent work. They were ■ handicapped greatly at first by having i> heavy and inadequate maps, but these i, were rapidly improved. On 3th August, 1918, when the Canadian and Australian 1 Corps delivered their great attaclc, only ; ouo German gun was able to reply, o\y- - ing to the excellence of the maps that had been prepared and the manner ill which the German guns had been previously spotted. 1 The result was that the British casualties were very small. The ( inapi) prejxired were solely for the use of (lie artillery and surveying, and in consequence had to be very accurate, especially for the twelve-inch British railway.,guns- , In the case of Big Bertha, which bombarded Paris, the Germans, he understood, had to make a half-milo correction in order to allow for the rotation of the earth during 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 i British soon followed the example set, and as usual defeated the Germans at their own game. Another valuable method adopted was that of air-burst ranging, in which the height of bursts was specially observed and deductions worked out therefrom. Sound-ranging, 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 was 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 pairs 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 i instruments gave prompt photographic 1 records, with the result that within four minutes of the receipt of the sound the position of a gun could be s/K,ttcd. A battery taken on by uouv.i could be settled very quickly. In one month early in 10 IS the Germans on the West- [ »;•-» iront lost as high as 13 per cent of I toir total guns through counter-battery