Safety lamp it. Air is drawn in and descends just inside the glass, passing up through the flame in the centre of the lamp. The outer casings of lamps have been made of brass or tinned steel. If a lamp bangs against a hard piece of rock a spark could be generated if iron or untinned steel were employed. Within months of Clanny's demonstration of his first lamp, two improved designs had been announced: one by George Stephenson, which later became the Geordie lamp, and the Davy lamp, invented by Sir Humphry Davy. Subsequently, Clanny incorporated aspects of both lamps and produced
Automatic lamp changer with high precision. The device automatically detects when the currently active lamp has ceased to function and moves the next lamp into place. The automatic lampchanger was invented by Charles Wallace and patented in 1928. This original model held two headlight lamps from a Model T automobile. The United States Lighthouse Service had these in common use by the 1930s, as they moved to convert all navigational lights to electricity. Lamp changers in current use may have two, four, or six lamps and use either a spring-loaded mechanism or an electric motor to change lamps when required. They are used