A claim that needs correcting
It is common to read that the telegraph was the first means of long-distance communication. That is not accurate. People sent signals over long distances for thousands of years before the electric telegraph of the 1830s and 1840s. What the electric telegraph changed was speed, reliability and the amount of information that could be carried, not the idea of signaling over distance. The word “telegraph” itself, from Greek words for “far” and “writing,” was first used for an optical system.
Messengers and the road
The oldest way to send a message was to send a person. Runners, riders and boats carried letters across empires. States built organized relay systems with stations where fresh horses and riders waited. Ancient Persia, Rome and China are among the best-known examples of official courier systems. They could cover long distances, but speed was limited by what a human or a horse could do, and messages could be intercepted or delayed.
Fire, smoke, drums and horns
Signals that travel faster than a person include light, smoke and sound. Beacon fires on hills, and later the lamp of a coastal lighthouse, could warn of an enemy approach, relaying the alert from one hilltop to the next. Beacon systems are recorded in ancient and medieval times in many places, including in the Mediterranean world, in China, where watchtowers lined frontiers, and in Britain, where they were used to warn of invasion.
Smoke signals served similar purposes among various peoples. Drums were used in parts of Africa and elsewhere to send messages over many miles, using patterns that imitated the tones of language. Horns, bells and cannons gave alarms.
These methods were fast but crude. A beacon could say “danger” or “the enemy has landed,” but it could not give details. A message had to be agreed in advance, and a single signal carried only one idea.
Signaling with more detail
Some ancient writers described attempts to send more detailed messages. The Greek historian Polybius described a method of signaling with torches in which letters were arranged in a grid, and the sender held up a number of torches to show a row and a column. The method could spell out words, though it required clear weather and practiced operators. Navies also developed flag codes for sailing ships. In the early nineteenth century, a code based on numbered flags, devised by a British naval officer, was used at the Battle of Trafalgar in 1805 for Nelson’s well-known signal to his fleet.
The Chappe optical telegraph
The first true system of long-distance written communication was optical. In France in the 1790s, Claude Chappe and his brothers developed a telegraph made of towers, each topped with a mast and a set of movable arms. An operator moved the arms into different positions that stood for letters, numbers or codes, and an operator at the next tower, watching through a telescope, copied the position and repeated it onward.
The French government adopted the system during the Revolutionary period. A line from Paris to Lille was in operation by 1794, covering well over 200 kilometers with a series of stations, and it was used to send news of military events. The network grew to cover much of France, and by the middle of the nineteenth century it included several hundred stations along thousands of kilometers of routes. Messages that would have taken days by rider could cross the country in a short time, depending on weather and the length of the message.
Other countries built optical systems of their own. Britain used shutter telegraphs, which displayed signals by opening and closing panels, between London and the coast, and Sweden built a network using a different design. Ships’ signaling and army field systems also grew out of these ideas.
Limits of the optical system
Optical telegraphs were impressive but limited.
- Weather and light. Fog, rain and darkness could block the view, and the system largely stopped at night.
- Manpower. Each tower needed trained operators, and a long line needed many stations in a chain.
- Cost. Building and staffing the towers was expensive, so lines were mostly state-owned and used for official business. The public had little access.
- Speed and capacity. Each signal took time to be copied and relayed, so the system could send only a few words per minute.
- Secrecy. Anyone who could see the towers could see the signals, although the code was secret.
Such constraints were acceptable for governments with urgent needs, but they limited the system’s usefulness for business or private messages.
The arrival of electricity
The movable arms resembled the later semaphore-style railway signals. Electric telegraphs overcame most of these limits. Wires worked at night and in bad weather, needed only operators at the ends, and could be extended cheaply along the lines of the early railways, and the same principle later led to wireless telegraphy. Signals traveled almost instantly. By the 1840s and 1850s, electric lines were replacing optical ones in Britain, France and elsewhere, and the towers fell out of use. Some survive as landmarks.
The right way to say it
A more accurate statement is that the electric telegraph was the first system to send messages over long distances almost instantly, in all weather, to anyone willing to pay. The beacons, drums and towers that came before it were earlier answers to the same problem, and the optical telegraph in particular showed how a network of relays could carry coded messages across a country.