Introduction To organize and depict, in abbreviated form, Alexander Graham Bell's invention of the telephone, we [1] have created a series of flowchart "maps" that include every sketch we have been able to locate from Bell's experimental notebooks, patents, depositions in court and correspondence. As the dates on the map indicate, time advances as on the maps from top to bottom. Multiple boxes spreading from right to left at the same time indicate that Bell was …showed first 75 words of 4819 total…

…showed last 75 words of 4819 total…with the amplitude of the vibration--that is, with the loudness of the sound; and the polarity of the current corresponds to the direction of the vibrating body--that is, to the condensations and rarefactions of air produced by the vibration.[30] The "body" he uses to illustrate these vibrations is his standard reed relay mechanical representation. Even though the Gallows telephone does not work, he knows he has discovered the theoretical principle behind a telegraph or telephone.