By 1837 Morse had developed a working one-wire model. It produced a zig-zag line on a strip of ticker tape, the dips of which could be decoded into letters and numbers with a special dictionary composed by Morse himself.
But it was Alfred Vail, a friend from New York University, who deserves much of the credit for what came next. At his family’s iron works in Speedwell, New Jersey, Vail made changes that resulted in a stylus that lifted up from the tape, leaving dots and dashes instead of a continuous line. According to Franklin T Pope, later a partner of Thomas Edison, Vail also simplified Morse’s awkward lookup system, using shorter codes for commonly used letters. The resulting system was much better; it did not require printing and instead could be ‘sound read’.
Regardless of who deserves the credit, in 1838, at an exhibition in New York, Morse transmitted 10 words per minute using what would forever be known as Morse code. In 1843, he received money from Congress to build a line from Baltimore to Washington DC, and, on 24 May 1844, sent the first inter-city message: “What hath God wrought!” By 1854 there were 23,000 miles of telegraph wire in operation across the US.
Morse code was later adapted to wireless radio. By the 1930s it was the preferred form of communication for aviators and seamen, and it was vital during the Second World War.