AUTOMATIC FOGHORN
Fog creeps np the Irish Channel. It grows denser. Titan suddenly from a lighthouse comes tho blaring, mournful blast of a foghorn. At regular intervals the waru- , ing is repeated. j If you climb up into this lighthouse in I ■Dublin, Ireland, you will see no one, for the warning is automatic. The fog itself sets the signal going. This remarkable ; device is the invention of a young professor of the National University of Ireland, ,1. j J. Dowling, according to the ‘ Popular I Science .Monthly." I A huge lamp tends a strong bcamrejf light slanting across the channel on to a largo window in the lighthouse. This window lens concentrates the light on a light, sensitive cell inside the lighthouse, producing an electrical effect that is magnified so that it operates an electrical relay- When tho light beam is dimmed by fog the relay current reverses, closing an electrical circuit that starts the foghorn. Ships going by, birds, airplanes, or other passing shadows have no effect _on the signal. 'Only persistent weakening of the light by fog operates the signal. Tho requires no attention, and for a year has operated successfully. I
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Bibliographic details
Evening Star, Issue 19274, 12 June 1926, Page 22
Word Count
195AUTOMATIC FOGHORN Evening Star, Issue 19274, 12 June 1926, Page 22
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