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 of Literature The list is online at the RSL website. Royal Society of Literature The Royal Society of Literature (RSL) is a learned society founded in 1820, by King George IV, to 'reward literary merit and excite literary talent'. The society is a cultural tenant at London's Somerset House. The society's first president was Thomas Burgess, Bishop of St David's (who was later translated as Bishop of Salisbury). The society maintains its current level of about 500 Fellows of the Royal Society of Literature: generally 14 new fellows are elected annually, who are accorded the privilege of using the post-nominal letters FRSL.