LAMPS LIT BY DARKNESS AND EXTINGUISHED BY DAYLIGHT

Manawatu Times, Volume LIV, Issue 6808, 11 January 1929, Page 3

LAMPS LIT BY DARKNESS AND EXTINGUISHED BY DAYLIGHT

For nine Months the street, lamps in Sheen Common Drive, Barnes, London, liavo been lighted by the agency of darkness and put out by the action of daylight. Local residents have been unaware of the wonder at work in their thoroughfares. On a recent evening I watched the miracle happening (says a special correspondent of the London Daily Mail.) As darkness fell the lamps, one by one ,lighted up simply because a selenium cell attached to them had been influenced by the fading light. The apparatus is technically known as a light-sensative selenium bridge. This is an apparatus which when connected across an. electric circuit lowers its electrical resistance if subjected to light—artificial or daylight. In the case of the street lamps in Barnes the mechanism switches the lamps on and off according to whether the selenium bvidgo is influenced by light or darkness. "Tim bridges affixed to the lamps in Sheen Common Drive," said Mr C. S. Davidson, chief engineer to the Barnes Urban District Council, "have not failed during the nine months wo have been using, them. We have kept the matter secret at the request of Radiovisor Patent, Ltd., which supplied them. The selenium bridges are affected equally by fog as by darkness."