WAR AND SCIENCE.

Taranaki Daily News, 13 December 1919, Page 12

WAR AND SCIENCE.

BRITISH ACHIEVEMENTS. SOME REMARKABLE PACTS. ANTI-SUBMARINE METHODS. An interesting review of the scientific developments made during the war was included in the Presidential address given by Sir C. A. Parsons at this year's meeting of the British Association. The President said that though British men of science had not formerly been adequately recognised in relation to war and the safety o£ their country, at the call of the sailors and the soldiers they whole-heartedly, and with intense zeal, devoted themselves to repair the negligence of the past, and to apply their unrivalled powers and skill to encounter and overcome the longstanding machinations of the enemy. They worked in close collaboration with the men of science of the Allied nations, and eventually produced better war material, chemicals, and apparatus of all kinds for vanquishing the enemy and the saving of our own men than had been devised by the enemy during many years of preparation planned on the basis of a total disregard of treaties and<the conventions of war.

A few figures would assist them to realise the great difference between this war and the preceding wars. At Waterloo, in 1815, 9044 artillery rounds were fired, having a total weight of 37.3 tons, while on one day during the last offensive in France, on the British front alone, 943,837 artillery rounds were fired, weighing 18,080 tons—over 100 times the number of rounds, and nearly 540 times the weight of the projectiles. Again, in the whole of the-South African War, 273,000 artillery rounds were fired, weighing approximately 2800 tons-; while during the whole war in France, orrtbs British front alone, over 170 million artillery rounds were fired, weighing nearly three and a half million tons—622 times, the number of rounds, and aiout 12ot> times the weight of projectiles. _ However great tliese figure* in. connection with .modem land artillery might be, they became almost insignificant when compared with those in respect of a modern naval battle squadron. The Queen Elizabeth, when firing all her guns, discharged eighteen tons of metal and developed 1,870,000 foot tons of energy. She was capable of repeating this discharge every minute, and when doing so developed by her guns an average of 127,000 effective horse-power, or more than one and a half times the power of her propelling machinery; and this energy was five times greater than the maximum average energy developed on the Western front by British guns. Furthermore, if all her guns were fired simultaneously, they would for the instant be developing energy at the rate of 13,132,000 horse" power. From these figures they can form some conception of the vast destructive energy developed in. a modern naval battle. LISTENING DEVICES.

I 'Probably the most interesting development during the war had been the extensive application of sound-listening devices for detecting and localising the enemy. The Indian hunter puts his ear to the ground to listen for the sound of the footsteps of his enemy. So'in modern warfare science had placed in the hands of the sailor and soldier elaborate instruments to aid the ear in tfie detection of noises transmitted through earth, water, air, or ether, and also in some cases to record these sounds graphically or photographically, so that their character and the time of their' occurrence might be tabulated. The sound-ranging apparatus developed by Professor Bragg and his son, by which the position of an enemy gun could be determined from electrically recorded times at which the sound wave from the gun passes over a number of receiving stations, has enabled our artillery to concentrate their fire on the enemy's guns, and often to destroy them. ■ • J

The French began experimenting in September. 1914, with methods of locating enemy guns by sound. The English section began work in October, ?915, adopting the French methods in the first instance. By the end*bf 191(5 the whol" front was covered, and sound-ranging began to play an important part in the location of enemy batteries. During 1917.locations by sound-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 be relied upon to give the position of an enemy gun to about fifty yards at 7000 yards range. It could also be carried on during considerable artillery activity. The apparatus for localising noises transmitted through the ground has been much used for the detection of enemy mining and counter-mining operations. Acoustic tubes, microphones and amplifying valves have been employed to increase the volume of very faint noises.

For many years before the war the Bell Submarine Signalling Company, of which Sir William White was one or the early directors, used submerged microphones for detecting sound transmitted through the water, and a submerged belt for sending signals to distances up to one mile. With this apparatus passing ships could be heard at a distance of nearly a mile when the sea was calm and the listening vessel stationary. HEARING THE INAUDIBLE. Of all the physical disturbances emitted or produced by a moving submarine, those most easily detected,' and n't the greatest distance, where the pressure waves set up in the water bv vibrations produced by the vessel and her machinery. A great variety of instruments had been devised during the war for delecting these nojses. depending on microphones and magnetophones of exceedingly high sensitivity. Among Ihem might be partie.ularlv mentioned the hydrophones devised by Captain Kyan and Professor Bragg, bcins adaptations of the telephone transmitter to work in water, instead of air. These instruments, when mounted so as to rotate, -were directional, being insensitive to sound waves' whose front is perpendicular to the plane of the diaphragm, and giving the loudest sound when the diaphragm was parallel to the wave front. Another preferable method for determining direction was to use two hydrophones coupled to two receivers, one held to each ear. This was called the biaural method, and enabled the listener to recognise the direction from which the sound emanates. When the vessel was 1 !n motion or the sea was rough the water noises from the dragging of the instrument throng)] the water and from the waves striking the &bis drowned &a goi&a* jfe«j» t>l"'

enemy vessel, and under such conditions the instruments were useless. The assistance of eminent was of invaluable help at this juncture. Experiments were made with sea-lions by Sir Richard Paget, who found that they had directional hearing under water up to speeds of six knots. Also Professor Keith explained, the construction of the hearing organs of the whale, the ear proper being a capillary tube, too small to be capable of performing any iiHeful function in transmitting sound to .the relatively large aural organs, tfhieh wore deep set in the head. The whole therefore heard by means of the sound waves transmitted through .the substance of the head. It was further seen that the organs of hearing of the whole to some degree resembled the hydrophone. The course, now became clear. Hollow towing bodies in the form of fell or porpoises were made of celluloid, varnished canvas, or very thin metal, and the dydrophone suitably fixed i„ the cen tre of the head. The body was tilled with water, and the cable towing the fish contained the insulated leads to the observer on board the vessel. When towed at some distance behind .the chasing ship disturbing noises were small and enemy noises could be heard up to speeds of fourteen knots, and at considerable distances. Thermionic amplifying valves had been extensively used and had added much to the sensitiveness of the hydrophone in its many forms. AERIAL DEVELOPMENT. It might be justly said that the development in aircraft design and manufacture was one of the astonishing engineering feats of the war. In .August, 1914 the British Air Services possessed a total of 272 machines, whereas in Octhe Koyal Air Force possessed over 22 - 000 effective machines. During the fest twelve months of the war the average monthly delivery of aeroplanes to outlying service was fifty, while during the last twelve months of the war the averages deliveries were 2700 per month So far as aero-engines were concerned! our position in 1914 was by no means satisfactory. We depended for a lar*e proportion of our supplies on other countries. In the aerial derby of 1913 of i-the eleven machines that started 'not ■one had a British engine. By the end tot the war, however, British acro-en-,gines had gained the foremost place in design and manufacture, and were well up to requirements as regards supply. Ihe total horse-power produced in the last twelve months of the war approximated to eight millions of brake horsepower a figure quite comparable with the total horse-power of the marine engine output of the county