Of course, Edisons most famous invention to come out of Menlo Park was the light bulb. Edison didnt invent electric lightsthere were arc lights already, which were similar to todays street lights. They were very, very bright so people didnt want them inside their houses. At home, people used gas lights, but their open flames were dangerous and they flickered a lot.Edison didnt just invent a light bulb, either. He put together what he knew about electricity with what he knew about gas lights and invented a whole system of electric lighting. This meant light bulbs, electricity generators, wires to get the electricity from the power station to the homes, fixtures (lamps, sockets, switches) for the light bulbs, and more. It was like a big jigsaw puzzleand Edison made up the pieces as well as fitted them together.One tough piece was finding the right material for the filamentthat little wire inside the light bulb. He filled more than 40,000 pages with notes before he finally had a bulb that withstood a 40 hour test in his laboratory. In 1879, after testing more that 1600 materials for the right filament, including coconut fiber, fishing line, and even hairs from a friends beard, Edison and his workers finally figured out what to use for the filamentcarbonized bamboo.The first large scale test of the system in the United States took place when Edisons Pearl Street station in New York Citys financial district sent electricity to lights in 25 builidings on September 4, 1882.