What did people use before the telegraph?
A semaphore telegraph, optical telegraph, shutter telegraph chain, Chappe telegraph, or Napoleonic semaphore is a system of conveying information by means of visual signals, using towers with pivoting shutters, also known as blades or paddles. Information is encoded by the position of the mechanical elements; it is read when the shutter is in a fixed position. These systems were popular in the late 18th – early 19th century. In modern usage, “semaphore line” and “optical telegraph” may refer to a relay system using flag semaphore.
