Electric light be made with a screw-thread base, two metal pins, two metal caps or a bayonet cap. The three main categories of electric lights are incandescent lamps, which produce light by a filament heated white-hot by electric current, gas-discharge lamps, which produce light by means of an electric arc through a gas, and LED lamps, which produce light by a flow of electrons across a band gap in a semiconductor. Before electric lighting became common in the early 20th century, people used candles, gas lights, oil lamps, and fires. Cornish chemist Humphry Davy developed the first incandescent light in 1802, followed
Royal Society Range Scott, who named the range after the Royal Society and applied names of its members to many of its peaks. For example, Mount Lister was named for Lord Joseph Lister, President of the Royal Society, 1895-1900. The Royal Society provided financial support to the expedition and its members had assisted on the committee which organized the expedition. The Royal Society Range consists of a Precambrian igneous and meta-igneous basement complex overlain by Devonian- to Triassic-age sandstones, siltstones and conglomerates of the Beacon Supergroup which dip shallowly westward away from the Ross Sea coast. The entire region is cut by north-south