Fire was one of the first sources that were harnessed by man both as a source of heat and a source of light. At first fire was something he had to find, but later he learnt how to produce fire himself, by striking stones together or by rubbing wood against each other, man leartn how to keep himself warm as well as how to see in the dark. Flint and iron pyrites were probably the first materials used by man to produce fire.
Torches of fire were the first mobile sources of light developed by man. A pole topped with any flammable material such as tar or a rag, was used as torch to guide people along dark ways.
As time passed, candles and earthernware was developed. A candle is popular even today, and is made of paraffin wax obtained from petroleum extracted from the centre of the earth. However, before the discovery of petroleum, candles used to be made of animal fat or bees wax. However these candles produced a lot of smoke but not much light.
Earthernware consisted of oil lamps made from clay, with a cmall reservoir with a wick which was lighted at the top. Gradually all the oil was used up due to capillary action in the wick. Evidences have revealed that even animal shells have been used as oil lamps by the ancient man. This oil mainly came from plants and the fat of sea animals. One of the first applications of these oil lamps was in lighthouses, one of which (one of the first few), the Pharos of Alexandria (which has been destroyed in the passage of time) is also one of the Seven Wonders of the Ancient World.
As petroleum and natural gas was discovered, the use of gas lamps popularised. The first gas lamps were simply jets of burning gas. Later 'mantles' were used to increase their brighness. Modern forms of these gas lamps are even being used today in some parts of the world.
As time passes, the 'era' of electric lighting began. The first electric lamp was the arc lamp, in which an electric current was made to jump acroess two carbon electrodes. Hoever, these lamps were very dangerous and prone to catching fire.
The invention of the electric light bulb is credited to two people today - Joseph Wilson Swan and Thomas Alva Edison. Swan's lamp had a carbon filament which glowed when current was passed through it. The catching of fire by the filament was achieved by reducing the amount of oxygrn in the bulb by evacuation. Edison's lamp was quite similar except that it consisted of a single-looped carbon filament.
A very common form of the modern bulb is the filament bulb, which has a tungsten filament inside a partially evacuated glass chamber that glows on the passage of current through it. Mercury discharge lamps and high and low pressure sodium lamps are also used commonly. Argon is a very common gas which is used in these bulbs. Tube-lights today have replaced bulbes in many houses since they are commercially and economically cheaper.