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
Brent Crude Brent Future based on ICE Futures Brent index at expiry. The index represents the average price of trading in the 25-day Brent Blend, Forties, Oseberg, Ekofisk (BFOE) market in the relevant delivery month as reported and confirmed by the industry media. Only published cargo size () trades and assessments are taken into consideration. The index is calculated as an average of the following elements: Brent Crude Brent Crude is a trading classification of sweet light crude oil that serves as a benchmark price for purchases of oil worldwide. This grade is described as light because of its relatively low density,