American inventor who founded a firm in Newark which invented wax paper and the mimeograph. In 1876, he set up a lab in Menlo Park, NJ. Here, he improved the telephone and telegraph and invented the phonograph. Using brute force trial and error, he came up with a scorched cotton thread (carbon) filament for a light bulb, the same solution arrived at by Swan. This filament, however, lasted 40 hours because Edison was able to maintain a good vacuum. He invested in DC power transmission and fought bitterly against Tesla and Westinghouse's AC transmission. In this decision, he was soon shown to be on the wrong side, as AC was much more convenient to transmit since it can be produced at high enough voltages to be transmitted over large distances, but DC could not. Edison also discovered the so-called Edison effect, which later led to the development of vacuum tubes. His slogan was "Genius is 1% inspiration and 99% perspiration."