SCIENCE IN WARFARE

Otago Witness, Issue 3495, 8 March 1921, Page 37

SCIENCE IN WARFARE

ASTONISHING FRENCH SECRETS. COUNTERACTING RAIDERS. Secret documents of the French War Office suggest that the next war will not be a war ol frightfulness in which enemy aviators will termy and destroy by means of the most powerful engines" conceivable, but it will be a conflict wherein nations will remain on an intell.-gpent defensive, matching their scientitio wits against powers of greater magnitude, and defeating by means of technical trickery any repetition of the illegitimate assaults by which the Central Powers endeavoured to force civilisation to bow to their will. These documents (remarks the New York Herald) outline the progress which has been made in the art of military camouflage, and they indicate that the war defence of the future will be marked by three distinct phasesof artistic trickery. , r^? erH will bo the creation of “fake areas in unimportant districts to represent vital or strategic areas such as munitionmaking towns or military headquarters. f lhLs plan proved its ji-ossibilities just before the conclusion of the armistice in November, 1918, when the French military authorities constructed on the outskirts of Paris a duplicate of the street lighting system of the town of St. Denis, including the munition factories of Aubervillers. This, when illuminated at night, provided so aitractive contrast to the darkened “real St. Denis” that the German airmen were completely deceived, and scores of their bombs were dropped in the midst of fields far away from the busy suburb at which tho German pilots aimed. The only real damage done was the smashing of a few hundred electric light globes. A “fake Paris” was actually started, but the signing of the armistice rendered unnecessary this tremendous expenditure. 2. Instead of darkening towns or factories when an enemy aeroplane attack is impending, the intruders of the future will be fought by light—plenty of light—which will surround Ins plane with a luminous cloud thousands of candle-power in strength, blinding the pilot and gunner, and making the attainment of any definite target impossible.. This is known ,as the system of “luminous Camouflage,” distinctly a French creation, and was used during the final month of the war for the protection of important factories in Eastern France The use of tliis measure was envisaged as an alternative to the creation of “deceptive targets’’ or “fake cities,” and could even have been put into operation for Baris at less expense than the more imaginative plan. So far had the preparations gone that the French army now has thousands of projectors in stock, ready with a few adjustments to send up cones of intense light rays which, by an easily calculated system of ray diffusion, could be so arranged as to leave Mother Earth, or at least any important portion of her surface, hidden in* absolute darkness as far as hovering airmen might, see. Nevertheless, beneath t,he ray cones factories could work at full blast, street lights could blaze without restriction, and even the taxi-cabs along the Champs Elysecs could be equipped with strong searchlights without fear of discovery from above. 3. Finally, a system of “obscurity camouflage,” through well-known chemical com--1 binations which evolve dense clouds of vapour, will be used in future wars to completely cover whole cities in the event of daylight attacks from the air. Experiments conducted along the Seine recently showed, that this phase of the science of aerial defence has progressed so far that clouds sufficiently “obscuring” can bo created in five minutes which will defy the skill of any aerial bomber. Of course, his bombs may drop on important positions, but the chances are against this occurring as often as if he were provided with a plainly visible target and accurate knowledge of his distances. The project- of creating false, cities to misdirect the attention of enemy aviators appears, on its surface, as fantastic as anything ever imagined by Jules Verne. Its promoters based their hope of success on the fact that enemy aviators, when desiring to locate a French town, invariably* d'd so by means of stream contours. Noticing that along the course of the Seine there are numerous bends which bear a great similarity to the contour of the Seine at Paris, it was suggested that one of these positions be chosen, and a “false Paris” built. Cost calculations, however, delayed this project, but it was decided to experiment on a smaller scale near Poissy-en-Franoe, where a replica of the munitionmaking district of St. Denis and the adjoining factories of Aubervillers was proposed. It was not to be a replica in the ordinary sense of the word, the French experts .deciding merely to lay out (on paper) the street lighting system of St. Denis, and then erect street lamps at regular intervale corresponding to the St. Denis “original.” The scheme was proved to be feasible, for tho cleverest French aviators, like their German opponents, were constantly mystified by the appearance of Aubervillers factories several miles from the position shown on the military maps. The anti-aircraft engineers promptly completed their plans for the building of the “fake Paris,” but while a few thousand street lights sufficed for the St. Denis experiment. the completion of the more elaborate scheme would have involved millions if Paris's myriad of small streets, each with a few feeble beacons, and the score of glaring railroad stations and centres like the Opera, tho Etolle, etc., were faithfully imitated. No less lacking in its imaginative quality is the idea of hiding well-lighted areas from the gaze of spying airmen by blinding them with a confusing concentration of more intense lumination. Such progress was made with this idea that a flood of light thrown up was so intense that it blinded the visiting airmen; and on several occasions the blast furnaces at Pompey, near Metz, wore able fo continue in operation without extinguishing their lights. Although tho bombers knew they were somewhere near the mills, they were unable definitely tQ locate tlieir target* and 75 per cent, of their bombs dropped harmlessly into neighbouring fields.