At the Centennial in Philadelphia, Alexander Graham Bell demonstrated his telephone to a small audience. As the son of the creator of a teaching method for the deaf and himself a teacher of the deaf, Bell possessed a far more refined and sophisticated understanding of phonetics than Edison, who was not present at the presentation. Edison also had a serious hearing problem: he was completely deaf in his left ear and almost completely deaf in his right. He compulsively, almost fanatically, recorded every word, thought, and action he deemed of practical value. Like Beethoven, another deaf man devoted to constant notetaking, Edison felt lost without a pencil and was constantly stuffing notebooks and sticky notes into his pockets.
