The development of portable lighting tools can be traced back to the early stages of human society-primitive society. Since humans learned to make fire by friction, portable lighting has evolved from fire, oil, and candles to flashlights. Portable lighting tools have undergone countless transformations, from torches, oil lamps, candles, and kerosene lamps to incandescent bulb flashlights, xenon bulb flashlights, and finally, a dazzling array of LED flashlights. Oil lamps have undergone numerous improvements. The oil used in oil lamps changed from animal oil to vegetable oil, and was eventually replaced by kerosene.
To prevent the wind from blowing out the flame, people added covers to oil lamps, from early paper covers to later glass covers. These oil lamps were not affected by the wind and were convenient for outdoor portable lighting. While using oil lamps, humans continued to search for other methods of portable lighting. Around the 3rd century BC, candles were made from beeswax. By the 18th century, candles made from paraffin wax appeared and began to be mass-produced by machines. More than 100 years ago, the British invented the gas lamp, taking a giant leap forward in human lighting methods. Torches, candles, oil lamps, and gas lamps-all portable lighting tools-rely on fire; they all rely on the light emitted by the combustion of substances for illumination. At the end of the 19th century, Edison invented the electric light bulb, thus rewriting the history of human lighting and ushering in the era of electric lighting.
