Edison's team had spent over a year testing materials for a long-lasting filament and had found that carbonised cardboard in a high vacuum could burn for many hours. To show that electric light could be practical, they lit the laboratory, nearby houses and lamps along the street, powered by generators in the lab. About 3,000 people came to see. Edison's real achievement was a complete system of generators, wiring, fuses and meters, which he opened in lower Manhattan in 1882.
Many inventors, including Joseph Swan in England, had made incandescent lamps, but they burned out quickly or needed too much current to be practical in a city-wide system. Edison set up his laboratory at Menlo Park in 1876 as an invention factory, and in 1878 he announced, prematurely, that he had solved the problem of electric lighting, sending gas-company shares tumbling.
The breakthrough came in October 1879, when a lamp with a carbonized cotton thread filament burned for more than 13 hours. The team soon turned to carbonized paper. In December the New York Herald published a long article on the invention, and crowds began arriving. On New Year's Eve, the Pennsylvania Railroad ran extra trains to Menlo Park, where visitors walked among lamps glowing along the lanes and in the laboratory.
Some visitors tried to break things, and a few lamps were stolen. Edison's team later found that carbonized bamboo lasted even longer. On September 4, 1882, his Pearl Street Station in Manhattan began supplying electricity to paying customers.
Key people: Thomas Edison, Francis Upton