Modern Lighthouse Lantern
In the earliest types of lighthouses open wood or coal fires were used as lights for the guidance of navigators. These were in due time replaced by tallow candles but their range was extrememly limited. Attempts were made to intesify the light by means of reflectors. The "modern" lighthouse is illuminated by huge hyperradiant lanterns lit by means of incandescent petroleum vapour, sometimes exceeding 1,000,000 candle power and weighing as musch as 20 tons.