NEW DEVICE FOR TRAPPING BURGLARS.

Star (Christchurch), Issue 18644, 22 December 1928, Page 5

NEW DEVICE FOR TRAPPING BURGLARS.

ALARM CONTROLLED BY INVISIBLE RAY. (Special to the “ Star.”) LONDON, November 1. Invisible rays which control burglar alarms are shortly to be introduced in the premises of a large West End firm in London, to safeguard the stock, worth nearly £1,500,000, from theft. This scheme ensures that if an intruder puts either his hand or part of his body in the path of a beam, an electric circuit is broken, and this immediately causes warning bells to be rung. A general tightening up of the anti-burglar system at the big London stores has taken place since the recent epidemic of thefts during the night. There is now a night patrol consisting of detective, fireman, and a trained dog. The patrol has to communicate with an office outside the building b\* pressing certain buttons at certain times, and if this is not done those on duty in the outside office immediately communicate with the police. There is also a secret alarm system so that if bandits overpower the patrol of force them to ring the “0.K.” signals at the appointed times the police will know what has happened. Invisible Ray Tested. Describing the invisible ray, a writer in a newspaper tells of a test in which he took part. He was in a room acting the part of a burglar, and his objective was a safe in the opposite corner of the room. The lights were switched off and the room was in complete darkness. “ I felt my way in the direction of the safe, moving .stealthily as becomes the best burglar,” says the writer. “ After taking a few steps a bell clanged. I stepped back in alarm. It would have gone on ringing, but the demonstrator cut it off. ‘ Try again,’ he said. I did so, this time walking on tip-toes. Again the bell rang. " I tried a new method, approaching the safe by a circuitous route and feeling my way along the wall. I was just thinking I had cheated the mvstery alarm when the bell clanged again. It was all very uncanny. I had touched nothing, except when I travelled via the wall, and felt nothing nor heard anything except a dull click as I came into the sphere of the invisible and intangible barrier. “ The demonstrator explained what had happened. When the bell rang it meant that I, or part of my body, had got into the path of the invisible ray. \ou have only to place vour hand in the ray to set the bell ringing. The Hidden Lamp. “To get to the safe there was no possible way of avoiding the ray. The rav itself came from a lamp hidden beneath a table placed alongside one wall of the room. I would never ha\e discovered it unless it had been pointed out to me. Even if I had and said ‘ that looks suspicious ’ and tried to tamper with it the bell would have rung. “If you look into the lamp vou can see nothing. This is because the lamp glass is a screen which eliminates the visible rays and permits only the invisible or infra-red rays to escape. Ihese are directed on to a little instrument concealed in the curtains on the other side of the room. It is very sensitive to light. *f s Ponds 0 nds even to the invisible ray. I his instrument is connected to the ordinary electrical circuit. When I crossed the path of the invisible ray the instrument was robbed of its influence. In other words, the circuit was interrupted, whereupon the instrument operated the alarm. The complete apparatus can tie worked by the normal electric supply in any house or building, and the current it uses is negligible.”