Graphite is an electrical conductor, hence useful in such applications as arc lamp electrodes. He also invented the Davy lamp and a very early form of arc lamp. He began to craft his own lantern, which he marketed as the Coleman Arc Lamp. High-intensity discharge lamps are a type of arc lamp. The source of the image was a glass slide, backlit by an arc lamp. In a carbon arc lamp, the electrodes are carbon rods in free air. They provided the intense concentrated light of an arc lamp but were easier to operate. The temperature of the arc in an arc lamp can reach several thousand degrees Celsius. The common fluorescent lamp is a low-pressure mercury arc lamp. It was used to power a single arc lamp in his art gallery. A Klieg light is an intense carbon arc lamp especially used in filmmaking. The xenon arc lamp is used when a continuous source of radiation is needed. These lamps used a carbon rod from an arc lamp rather than a slender filament. Thus, it can be used in, for instance, electrical arc lamp electrodes. In Paris, the electric carbon arc lamp first came into use in the 1840s.