THE DEATH RAY.

Auckland Star, Volume LIX, Issue 225, 22 September 1928, Page 18 (Supplement)

THE DEATH RAY.

BUT NOT YET.

SECRETS OF A X WEAPON.

IN WORLD WARFARE.

(By PROFESSOR A. If. LOW.)

The popular idea of the death ray is of some wireless transmitter which sends electricity to a distance, and which can be controlled by the operator at will. It has even been suggested that euch a device in the hands of the League of Nations would prove an excellent missionary of peace, although the irony of such statements passes unnoticed. Unfortunately for the inventor, it is not particularly easy to kill people by electricity. In America great care has to be taken to connect the bodies of unfortunate criminals in such a manner that the current passes through vital I parts of the anatomy, and it is still quite common for persons to receive severe » shocks without causing sufficient para- ; lysis to produce ultimate death. Horses can be killed very much more easily than men, as was demonstrated i in the days of tramcars driven by road contacts, so that the electrical death ray might be found useless for such important purposes as the destruction of rats or vermin were it to be discovered toi- morrow. * Most people who are injured electrically probably expire from shock consequent upon burning, and this burning implies the existence of relatively high currents of electricity. The human body has considerable resistance, and even when the skin is wet enough to allow currents to pass over the surface it is only possible to give the actual "knock-out" by a current of about l-10th of an ampere or as much as commonly passes through an electric lamp in the home. The shocks which are felt by people who touch sparking plugs on motor cars or who use medical coils have high pressure behind them, but very little actual power. Would Not Lift a Feather. In this statement lies the difficulty of the death ray. A wireless station, with the partial exception of the beam transmitter, sends signals broadcast, and although crops and even children may benefit from the ethereal waves, there is insufficient power to affect either the weather or the "beasts of the field." At a very short range from the largest radio station in the world the energy available would hardly suffice to move a feather. The power is disseminated and is transmitted inefficiently to a hopeless degree. The control of airships, battleships, and torpedoes by wireless is quite a different matter, and has been brought to a remarkable pitch. 1 Torpedoes have been steered by aeroplanes-at a distance of many miles, and there is no doubt that in the far future warfare will be usefully conducted on these lines. It will be possible for hidden armies to control high-flying bomb-carrying vessels or water torpedoes travelling under the sea to a range of many miles, even perhaps beyond the limits of direct vision. It is more than probable that within 50, years it-will be a simple matter to drop a tonnage of bombs on London from 200 miles distance which would in one day exceed the paltry 50 tons which fell over London during the whole period of the war, It can hardly be doubted that some form of radio spying by television will be produced, that bacteriological bombs 1 will come upon us from a distance in pilotlese aeroplanes, while perhaps in the dim and.distant future we may find our j very thoughts being read or stultified by the use of radio.

All these pleasant little happenings are impracticable to-day. We can send an infinitesimal directing signal to an apparatus on a battleship, .vhich in turn switches on or off the power of that ship, but we cannot transmit any pqwer worth mentioning over long distances. Violet Light Death. Experiments have been made quite recently by mean* of short-wave transmitters which are more or less directional, but we have.not achieved a shortness of wave which would ultimately render the radio signal visible iike light and; we have only produced, by the use of immense power, a' wave which induces high temperatures in the bodies of people standing in its path, like some therapeutic apparatus on a huge scale. It is not a difficult matter to light lamps at short distances by radio, but the power received is out* of all proportion to that transmitted, and it is not in a form .whlph would produce any ill effects worth mentioning upon the human body. The very suggestion that animals and people could be killed by a single or vortex directional death ray is at present altogether beyond the scope of modern knowledge, but not beyond possibility of future conception with the almost daily increase of under? tanding takine place in the world. I It has been suggested that some forms of ultra-violet light might be capable of carrying death rays, but here again the application to killing, if sensational, is far foom easy. One of the greatest difficulties with ordinary wireless lies in its lack of direction and pure selectivity. Were anyone to invent some method of producing a true ray, the obvious use for such a^ device would be its employment for .signalling where the power required is virtually negligible. Such an invention would be worth untold millions, and it is strange that many inventors of killing rays do not employ them in the first instance for so relatively simple and for so obvious a purpose. Experiments have been conducted with a view to the production of induced currents in the metallic parts of aeroplanes, in order that wires might be burned and magnetos damaged* Such schemes are still impracticable for the time being, and indeed are of less use to military aeronautics than aerial torpedoes, controlled rockets, and nets suspended from balloons. TJiere is no really successful method toniay of coping .ith a determined invasion by air, other than at terrible nak to the lives of the defenders. The Latest Plan. *i.?* he * latest death rav suggestion * is t£at of a wave of high frequency sound. W 8 W f" known ' haa a destrucilZlfVi °? human 8 - eve n when it cannot be heard. It i 8 for this reason redL^f 11 ,* B .*"* 8 * 8 laid U P° n the SSy, effi . C,eilc y and general health SJSL rhy v thmic noißes of modern civilisation which so easily carry other

sounds upon their own waves; there are many victims of shell shock who owe their condition entirely to the attack of noise. The production of high frequency vibratory effectß in the air is not particularly difficult, and such high notes which ar© audible only to birds and animals can be maintained by the same mean adopted to keep the wave length of an.ordinary broadcasting station definitely fixed. Oscillation at vastly higher frequencies than that audible to any living creature at present known might conceivably produce a wearing or even damaging effect upon life, but tho difficulty is that of transmission.

Fish of some kinds can be killed by high-pitched sounds, but human beings are not likely to submerge themselves in water in order that vibrations might be transmitted to them. The air is a very plastic substance, which absorbs and distorts sound waves transmitted through its agency.