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
Canadian Crude Index futures contracts: A fixed price contract, which represents the price of crude oil at Cushing, Oklahoma, and a basis differential contract, which represents the difference in price between Cushing and Canada. Both contracts are priced in U.S. dollars per barrel. Together, these create a fixed price for Canadian crude oil. The Index value is determined by its third-party calculation and publication agent, the NYSE Global Index Group, based on daily returns of prices published by ICE Futures Europe. Canadian Crude Index The Canadian Crude Oil Index (CCI) serves as a benchmark for oil produced in Canada. It allows investors to