A PASSING SHADOW MAY WORK A BATTLESHIP

Sun (Auckland), Volume 1, Issue 70, 14 June 1927, Page 7

A PASSING SHADOW MAY WORK A BATTLESHIP

WONDERS OF MODERN SCIENCE A passing shadow or a dewdrop may now turn on the lights of a city, start or stop a railroad train, or manoeuvre a battleship. These results, apd others quite as marvellous, and brought about by a device for controlling electric power, so sensitive that it can be operated by the mere approach of the human hand. Its inventor is D. J). Knowles, research engineer ofc the Westinghouse Electric and Manufacturing Company. To illustrate the sensitiveness of this device, we are told in a press bulletin issued by the Westinghouse News Service, a watch is laid upon a plush cover on a small table. Though the watch is in no way connected with an electric circuit, any attempt to pick it up results in ringing a bell and lighting a light. It is not necessary to touch the watch —the alarm goes off as soon as the hand comes within a few inches of it. The same thing happens when attempts are made to touch a picture or pick up silverware from a plate. The alarm is also sounded when water is dropped from an eye-dropper upon two small parallel wires, and also when the flame of a match is held beneath the wires. By connecting a tiny pho-to-electric tube in the circuit, the device is made sensitive to light and operates when the window-shade is raised and lowered or when the shadow of the hand is cast upon it. The device causing these effects is a tube which closely resembles a radio tube in size and appearance, but which lights up with a pinkish glow whenever it operates. Dewdrop May Light a City The invention is known as the Knowles Grid—Glow Tube. Mr. Knowles is only twenty-eight years old. He explains: “This tube is a relay, that Is to say, it is a device which is operated by a small current and controls a much larger one. The ordinary relays used in electrical engineering control a current 10,000 times greater than the current controlling them. But any tube has an amplifying power of around one hundred million, and it is probably by far the most sensitive thing of the kind ever devised. “The energy required to operate it is about one-billionth of a watt, or about one-fortieth of the amount of energy exerted by a fly crawling vertically upward one inch in one second. This infinitesimally small amount of energy is sufficient to start flowing through the tube a current that will close or open a switch handling upward of twenty-five amperes: and this in turn is ample for controlling almost any operation. Thus it is quite possible by the use of this relay for a passing shadow or a dewdrop to turn on the lights of a city, start or stop a railroad train, or manoeuvre a battleship.”