electric lighting. By 1881, the Savoy Theatre in London was using incandescent lighting. While electric lighting was introduced to theatre stages, the gas mantle was developed in 1885 for gas-lit theatres. "This was a beehive-shaped mesh of knitted thread impregnated with lime that, in miniature, converted the naked gas flame into in effect, a lime-light." Electric lighting slowly took over in theatres. In the 20th century, it enabled better and safer theater productions, with no smell, relatively very little heat, and more freedom for designers. Decline In the early 20th century, most cities in North America and Europe had gaslit streets, and most railway station platforms had gas lights too. However, around 1880 gas lighting for streets and train stations began giving way to high voltage (3,000–6,000 volt) direct current and alternating current arc lighting systems. This time period also saw the development of the first electric power utility designed for indoor use. The new system by inventor Thomas Edison was designed to function similar to gas lighting. For reasons of safety and simplicity it used direct current (DC) at a relatively low 110 volts to light incandescent light bulbs. Voltage in wires steadily declines as distance increases, and at this low voltage power plants needed to be within about of the lamps. This voltage drop problem made DC distribution relatively expensive and gas lighting retained widespread usage with new buildings sometimes constructed with dual systems of gas piping and electrical wiring connected to each room, to diversify the power sources for lighting. The development of new alternating current power transmission systems in the 1880s and 90s by companies such as Ganz and AEG in Europe and Westinghouse Electric and Thomson-Houston in the US solved the voltage and distance problem by using high transmission line voltages, and transformers to drop the voltage for distribution for indoor lighting. Alternating current technology overcame many of the limitations of direct current, enabling the rapid growth of reliable, low-cost electrical power networks which finally spelled the end of widespread usage of gas lighting. Modern outdoor usage In some cities, gas lighting is preserved or restored as a vintage nostalgic feature to support the historic atmosphere of their historic centres. In the 20th century, most cities with gas streetlights replaced them with new electric streetlights. For example, Baltimore, the first US city to install gas streetlights, removed nearly all of them. A sole, token gas