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The first arc light was the carbon type. They existed in the 19th century and underwent various forms of improvement before being abandoned. Problems with the lights included hot sparks which often burned people and started fires. From a partial glass fixture to later development leading to the enclosed carbon arc light which limited oxygen exposure to the electrodes and improved longevity this type of arc light was eventually abandoned in favor of a sealed mercury vapor arc light.The first arc light was the carbon type. They existed in the 19th century and underwent various forms of improvement before being abandoned. The first arc lamp to be used in large numbers was known as the Jablochkoff Candle, developed in 1876 by a Russian telegraph engineer. The use of the arc light peeked around the year 1910. Problems with the lights included hot sparks which often burned people and started fires. From a partial glass fixture to later development leading to the enclosed carbon arc light which limited oxygen exposure to the electrodes and improved longevity this type of arc light was eventually abandoned in favor of a sealed mercury vapor arc light. The modern fluorescent light is a type of low pressure mercury arc light. The fluorescent tube is filled with mercury vapor gas. When the lamp is turned on, electrical currents excite the mercury vapor, causing it to emit ultraviolet light which is then filtered using a phosphor coating to reduce rays to visible light. The fluorescent bulb is a hybrid utilizing the principle of the arc light, however, is different in design as well as application. The mercury arc produces a bluish light that renders colors poorly. Therefore, most mercury vapor lamps have a phosphor coating that alters the color temperature and improves color rendering to some extent. Most street lights once used Mercury vapor bulbs but have since been replaced by low pressure sodium lighting. Mercury vapor lamps provide about 50 lumens per watt, but ballast loss can reduce the system efficacy to about 30 lumens per watt. Mercury vapor lamps were the first high intensity discharge lamps to be commercially available for a wide variety of lighting applications. They use an electric arc through vaporized mercury to produce light. The advantages of Mercury vapor lighting is that it's more energy efficient than incandescent and most fluorescent lights, especially for outdoor applications The mercury arc produces a bluish light that renders some colors poorly. Therefore, most mercury vapor lamps have a phosphor coating that alters the color temperature and improves color rendering to some extent. Most street lights once used Mercury vapor bulbs but have since been replaced by low pressure sodium lighting. Mercury vapor lamps provide about 50 lumens per watt, but ballast loss can reduce the system efficacy to about 30 lumens per watt. There are still a lot of mercury vapor lights in rural America. The are common in the Midwest for the lighting and security on farms. Light service is often provided by the local electric utility company.There are still a lot of mercury vapor lights in rural America. The are common in the Midwest for the lighting and security on farms. Light service is often provided by the local electric utility company. Mercury vapor lighting is becoming obsoleted by metal halide and ceramic metal halide lights.