In the film, Edison and his wife communicate with each other by tapping out Morse code. In the movie this is presented as a charming endearment, but in fact Edison was so deaf the only way he and his wife could talk was by tapping Morse code on each other's hands.
This was one of the films that Spencer Tracy really believed in and actively supported not because he starred in it, but because he was a great admirer of Thomas Edison. This was unusual as Tracy was known throughout most of his career to disparage his own gifts as well as the importance of motion pictures. Also, prior to this film Spencer Tracy had been a very active member of the "Academy of Motion Picture Arts and Sciences". He even hosted the awards show on at least one occasion. However when the nominations came out for the best films of 1940, Tracy was appalled that "Edison the Man" was so overlooked in the nominations. It was only nominated for best writing. Tracy swore he would never attend another academy award ceremony again. He never did. Not without irony is that although he was nominated another 6 times over the next 28 years, Tracy never won another Oscar after that after winning two in a row in the previous two years.
The World Premiere for this film in Edison's hometown of West Orange, New Jersey, serves as the backdrop for the mystery novel, 'Dead at the Box Office' by John Dandola. The novel explains in great detail how M.G.M. went about planning and carrying out the festivities.