The History of the Carbon Arc Lamp

The Carbon Arc Lamp was first invented by Humphry Davy in the first 10 years of the 1800s. However, it wasn't widely used until the 1870s when people started using it for street lights and large buildings. The arc lamp didn't have a very long life, because incandescent lights started to get popular in the early 1900s, but it's still a interesting invention. The arc lamp works by creating an electric arc between 2 carbon electrodes in the air.
Advantages of the carbon arc lamp:

• Cheaper than gas or oil lights
• Very bright
• The only large area electric light during the 19th century

Disadvantages of the carbon arc lamp:

• The carbon rods in them had to be replaced frequently, becoming a full time job in some cities
• Creates lots of radio frequency interference
• Fire hazard
• Emits a lot of carbon monoxide which can be a big problem if used inside

How it works: An electric arc passes through the air between 2 carbon rods. The gap must be a perfect size, because if it's too big, it'll go out, and if it's too narrow, it won't produce enough light. Carbon gets vaporized in the very high temperature of the arc, which is around 6500 F. Carbon vapor is bright, and that's why people chose to use carbon instead of any other flammable substance.

While the carbon arc light was very cool when it started to be sold and many people wanted them, there were some major drawbacks. These included sparks that fall off the light and can start fires, and it also produces UV-a, b, and c light which is harmful to the skin and the eyes.