Edison set up his laboratories and factories at Menlo Park, New Jersey, in 1876, and it was there that he invented the phonograph, for which he received the first patent in 1878. It was there, too, that he began that wonderful series of experiments which gave to the world the incandescent lamp. He had noticed the growing importance of open arc lighting, but was convinced that his mission was to produce an electric lamp for use within doors. Forsaking for the moment his newborn phonograph, Edison applied himself in earnest to the problem of the lamp. His first search was for a durable filament which would burn in a vacuum. A series of experiments with platinum wire and with various refractory metals led to no satisfactory results. Many other substances were tried, even human hair. Edison concluded that carbon of some sort was the solution rather than a metal. Almost coincidently, Swan, an Englishman, who had also been wrestling with this problem, came to the same conclusion. Finally, one day in October, 1879, after fourteen months of hard work and the expenditure of forty thousand dollars, a carbonized cotton thread sealed in one of Edison's globes lasted forty hours. "If it will burn forty hours now," said Edison, "I know I can make it burn a hundred." And so he did. A better filament was needed. Edison found it in carbonized strips of bamboo. Edison developed his own type of dynamo, the largest ever made up to that time, and, along with the Edison incandescent lamps, it was one of the wonders of the Paris Electrical Exposition of 1881. The installation in Europe and America of plants for service followed. Edison's first great central station, supplying power for three thousand lamps, was erected at Holborn Viaduct, London, in 1882, and in September of that year the Pearl Street Station in New York City, the first central station in America, was put into operation. The incandescent lamp and the central power station, considered together, may be regarded as one of the most fruitful conceptions in the history of applied electricity. It comprised a complete generating, distributing, and utilizing system, from the dynamo to the very lamp at the fixture, ready for use. It even included a meter to determine the current actually consumed. The success of the system was complete, and as fast as lamps and generators could be produced they were installed to give a service at once recognized as superior to any other form of lighting. By 1885 the Edison lighting system was commercially developed in all its essentials, though still subject to many improvements and capable of great enlargement, and soon Edison sold out his interests in it and turned his great mind to other inventions.