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 Fellow of the Royal Society said "The objects of the Royal Society are nothing to do with the monarchy, and the monarchy, on the whole, has shown absolutely no interest in science". In the past members of foreign royal families have also been elected Royal Fellows. Royal Fellow of the Royal Society A Royal Fellow of the Royal Society is a member of the British Royal Family who has been elected a Fellow of the Royal Society. The council of the Royal Society recommends members of the Royal Family to be elected and then the existing Fellows vote by a secret ballot whether to accept