A long, long time ago, before electricity, fire was the only weapon against darkness. Ancient civilizations made use of torches but by 4500 B.C. oil lamps made out of shells or hollow rocks were in use. Candles were introduced some 1500 years later. Oil lamps burned plant- and animal-derived oils, whilst candles burnt wax and tallow. While the light produced was sufficient to read at night, it was too soft and localized to illuminate any significant space. In addition, wax and oil were high maintenance, necessitating regular trimming of the wick, and their portable vehicles constantly threatened spillage. Society was looking for more, and one of the most popular resources of the late 1700鈥檚 provided the answer.聽
In 1792, William Murdoch, a Scottish inventor, equipped his home with pipes that delivered coal gas to lamps, giving birth to 鈥済as聽lighting. The coal gas combined with oxygen in the air to produce carbon dioxide, water vapour, heat and light. Coal gas is made by burning coal inside a closed container, which separates its constituent parts into hydrogen, carbon monoxide, and methane, as well as some solid by-products. Other common gaseous fuels include propane, butane, and ethylene. Sound familiar? These are still used for camping stoves, where a light, compact, and reliable fuel comes in handy.
Since coal gas flowed through pipes in large volumes, its combustion produced light far more efficiently than candles. Murdoch was eventually able to reproduce his feat outside his building and people were so enthralled by the new bright light that it gave rise to a new industry. By the early 1800鈥檚, Paris and London had installed gas lamps along their streets. The added light increased accessibility and demand for nighttime activities, changing the nighttime culture from one of shutting oneself in to going out and socializing with others.聽
However much of an improvement gas lights were to candles, they weren鈥檛 necessarily low-maintenance - the lamps had to be manually lit every night and extinguished every morning. Even worse, there were harmful side effects, as carbon monoxide, a lethal gas, was a byproduct of the combustion reaction. Around the turn of the 20th century, almost all street lamps were replaced with electric lightbulbs, providing cleaner, safer, brighter, more efficient lighting.聽
Morgan Sweeney聽is studying Cognitive Science currently and in 4th year at 成人VR视频.
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