NEW WAR DEVICE.

Auckland Star, Volume LXVI, Issue 269, 13 November 1935, Page 15

NEW WAR DEVICE.

INFRA-RED DETECTOR.

SHIPS AND 'PLANES IN FOG. LONDON, October 5. An instrument has been submitted for inspection at the War Office which, it is claimed, can detect ships at a distance of 13 miles hidden iu fogiand aeroplanes at a height of 20,000 feet. It is among the' inventions and ideas which are being considered by the British Government scientific committee on means of defence against aircraft and is an application of infra-red rays as a substitute for searchlights. The instrument is not unduly fragile and its effectiveness is not impaired by vibration. On the other hand, thte presence of carbon in- the air, or in a cloud of fog, interferes with its powers. This sort of interference would be very great over and around London, where there is frequently much suspended soot. Also, it is believed that ships and aeroplanes could protect themselves to a large extent from the operation and detection of the instrument in its present form by the use of smoke screens. Research, however, is being carried in, and it is reasonable to hope that many, if not all, the minor difficulties may eventually be overcome. The importance of such a means of defence in detecting ships and aircraft is obvious. When mist destroys the effectiveness of the searchlight the infra-red rays may tell a tale of significant movements, and may thus prevent surprise, besides ensuring considerable accuracy of firing against the unseen enemy. One small smudge, or a group of tiny smudges in successive positions, might solve a difficult riddle and lead to action. In the ■ ease of aircraft, which look like the merest specks at a height of three or four miles, and even then only seen in favourable conditions, it would seem that the infra-red rays would be hardly likely to have invariable success. But there are many other purposes to which such a device could 1w put. '