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
Signal lamp Signal lamp A signal lamp (sometimes called an Aldis lamp, after Arthur Cyril Webb Aldis who invented a widely used design, or a Morse lamp) is a visual signaling device for optical communication, typically using Morse code. Modern signal lamps are focused lamps which can produce a pulse of light. In large versions, this pulse is achieved by opening and closing shutters mounted in front of the lamp, either via a manually operated pressure switch or, in later versions, automatically. With hand held lamps, a concave mirror is tilted by a trigger to focus the light into pulses. The lamps