Thomas Edison of the Edison patent to charge a more reasonable rate for the use of the Edison patent rights and lowering the price of the electric lamp. On October 8, 1883, the US patent office ruled that Edison's patent was based on the work of William E. Sawyer and was, therefore, invalid. Litigation continued for nearly six years, until October 6, 1889, when a judge ruled that Edison's electric light improvement claim for "a filament of carbon of high resistance" was valid. To avoid a possible court battle with Joseph Swan, whose British patent had been awarded a year before Edison's,
Edison State Park development laboratory in Menlo Park was the first of its kind in the world. On October 22, 1879, Thomas Edison tested a bamboo filament which lasted over 30 hours, which was used to create the first successful incandescent light bulb. This accomplishment followed Edison's testing of over a thousand filaments in six months. 3 years earlier, Thomas Edison tested his wax and tinfoil phonograph by recording and playing "Mary Had a Little Lamb." Thomas Edison improved Alexander Graham Bell's telephone using carbon. In addition, he invented an electric train and tested it on a track built around his laboratory, now