The fact that an electric spark in the presence of air between two carbon rods is capable of producing a very bright light still baffles many. These two carbon rods must have a gap of the right size in between for effective lighting. The bigger the gap, the more the flicker. This phenomenon is what is referred to as Electric “arc” lighting. The arc light was invented by Humphry Davy in the first decade of the 1800s. It was the first practical electric light that was widely used as a source for streets, theaters, and large building lighting.