The first great invention developed by Edison in Menlo Park was the tin foil phonograph. While working to improve the efficiency of a telegraph transmitter, Edison noted that the tape of the machine gave off a noise resembling spoken words when played at a high speed. This caused him to wonder if he could record a telephone message. Edison began experimenting with the diaphragm of a telephone receiver by attaching a needle to it. He …showed first 75 words of 4059 total…

…showed last 75 words of 4059 total…A. Edison, Inc. Much later, he founded his own company, Calibron Industries, Inc., and built his own smaller laboratory in West Orange. He earned over 80 patents in his career. In 1925 he married Anna Maria Osterhout, who was also a student at MIT. In later years he became an ardent environmentalist, opponent of the Vietnam War and advocate of Zero Population Growth. He lived in West Orange with his wife Anna until his death on November 24, 1992.