At the start of the 19th century news could move no faster than its carrier. A letter took weeks by ship from London to New York, days by horse post from Paris to Vienna. The idea that electricity could carry signals had been known since the 18th century; in 1837, in Britain, William Cooke and Charles Wheatstone patented a multi-needle electric telegraph for railway signalling. In the United States the painter Samuel Morse, inspired by a shipboard conversation with a physician named Jackson, developed a simpler and more robust alternative: a single line, a single circuit, and the dot–dash code that now bears his name.

In 1843 Congress granted Morse $30,000 to build a 60-kilometre experimental line between Washington and Baltimore. The engineer Ezra Cornell first tried to bury the wires; that failed and they were finally strung on wooden poles. On 24 May 1844, Morse sent the message "What hath God wrought" (Numbers 23:23) from the Supreme Court chamber to his assistant Alfred Vail in Baltimore. The message arrived in seconds. A few months later the line carried results of the Democratic Party convention in Baltimore back to Washington in real time — politics became something that could be followed minute by minute.

The spread was rapid. In 1846 the Associated Press was founded to gather news over the wires; in 1851 Paul Julius Reuter opened his agency in London; the same year a cable was laid under the English Channel. During the American Civil War (1861–65) the telegraph let Lincoln manage the front from the White House; stock prices between cities now moved with seconds of delay rather than hours. Diplomat, merchant, journalist, soldier — all were shifted at once onto a new time scale.

The American historian James W. Carey wrote that the telegraph "for the first time in history permitted the separation of communication from transportation": until then, a message moved no faster than the body, horse, or ship carrying it. After Morse, news became a different kind of entity from the idea — it could travel from one place to another without moving any matter. That separation became the conceptual foundation of every communication network of the next century and a half — telephone, radio, the internet; the single line transmitted in May 1844 was not an abstract technical marvel but the first pulse of the modern world's nervous system.