Smoke signal

Last updated
Native Americans on a painting by Frederic Remington Frederic Remington smoke signal.jpg
Native Americans on a painting by Frederic Remington

The smoke signal is one of the oldest forms of long-distance communication. It is a form of visual communication used over a long distance. In general smoke signals are used to transmit news, signal danger, or to gather people to a common area.


History and usage

In ancient China, soldiers along the Great Wall sent smoke signals on its beacon towers to warn one another of enemy invasion. [1] [2] The colour of the smoke communicated the size of the invading party. [1] By placing the beacon towers at regular intervals, and situating a soldier in each tower, messages could be transmitted over the entire 7,300 kilometres of the Wall. [1] Smoke signals also warned the inner castles of the invasion, allowing them to coordinate a defense and garrison supporting troops. [2]

In ancient Sri Lanka, soldiers stationed on the mountain peaks would alert each other of impending enemy attack (from English people, Dutch people or Portuguese people) by signaling from peak to peak. In this way, they were able to transmit a message to the King in just a few hours. [3]

Misuse of the smoke signal is known to have contributed to the fall of the Western Zhou Dynasty in the 8th century BCE. King You of Zhou had a habit of fooling his warlords with false warning beacons in order to amuse Bao Si, his concubine. [4]

Polybius, a Greek historian, devised a more complex system of alphabetical smoke signals around 150 BCE, which converted Greek alphabetic characters into numeric characters. It enabled messages to be easily signaled by holding sets of torches in pairs. This idea, known as the "Polybius square", also lends itself to cryptography and steganography. This cryptographic concept has been used with Japanese Hiragana and the Germans in the later years of the First World War.

North American indigenous peoples also communicated via smoke signal. Each tribe had its own signaling system and understanding. A signaler started a fire on an elevation typically using damp grass, which would cause a column of smoke to rise. The grass would be taken off as it dried and another bundle would be placed on the fire. Reputedly the location of the smoke along the incline conveyed a meaning. If it came from halfway up the hill, this would signify all was well, but from the top of the hill it would signify danger.[ citation needed ]

Smoke signals remain in use today. The College of Cardinals uses smoke signals to indicate the selection of a new Pope during a papal conclave. Eligible cardinals conduct a secret ballot until someone receives a vote of two-thirds plus one. The ballots are burned after each vote. Black smoke indicates a failed ballot, while white smoke means a new Pope has been elected.

Colored smoke grenades are commonly used by military forces to mark positions, especially during calls for artillery or air support.

Smoke signals may also refer to smoke-producing devices used to send distress signals. [5] [6]


Native Americans

Lewis and Clark's journals cite several occasions when they adopted the Native American method of setting the plains on fire to communicate the presence of their party or their desire to meet with local tribes. [7]


Yámanas of South America used fire to send messages by smoke signals, for instance if a whale drifted ashore. [8] The large amount of meat required notification of many people, so that it would not decay. [9] They might also have used smoke signals on other occasions, thus it is possible that Magellan saw such fires (which inspired him to name the landscape Tierra del Fuego) but he may have seen the smoke or lights of natural phenomena. [10] [11]

Noon Gun

The Cape Town Noon Gun, specifically the smoke its firing generates, was used to set marine chronometers in Table Bay.

Aboriginal Australians

Aboriginal Australians throughout Australia would send up smoke signals for various purposes. [12] [13] [14] [15] Sometimes to notify others of their presence, particularly when entering lands which were not their own. [12] Sometimes used to describe visiting whites, smoke signals were the fastest way to send messages. [15] Smoke signals were sometimes to notify of incursions by hostile tribes, or to arrange meetings between hunting parties of the same tribe. This signal could be from a fixed lookout on a ridge or from a mobile band of tribesman. [14] "Putting up a smoke" would often result in nearby individuals or groups replying with their own signals. [13] [14] To carry information, the colour of the smoke was varied, sometimes black, white or blue depending on whether the material being burnt was wet grass, dry grass, reeds or other, and the shape of the smoke could be a column, ball or smoke ring. This message could include the names of individual tribesmen. [14] Like other means of communication, signals could be misinterpreted. In one recorded instance, a smoke signal reply translated as "we are coming" was misinterpreted as joining a war party for protection of the tribe when it was actually hunting parties coming together after a successful hunt. [14]


Modern aviation has made skywriting possible.


  1. 1 2 3 Ivan, Djordjevic (2010). Coding for Optical Channels. Springer US. p. 2. ISBN   978-1-4419-5569-2. OCLC   699999686.
  2. 1 2 Du, Yumin; Chen, Wenwu; Cui, Kai; Guo, Zhiqian; Wu, Guopeng; Ren, Xiaofeng (2021-02-16). "An exploration of the military defense system of the Ming Great Wall in Qinghai Province from the perspective of castle-based military settlements". Archaeological and Anthropological Sciences. 13 (3). doi:10.1007/s12520-021-01283-7. ISSN   1866-9557. S2CID   231940516.
  3. Knox, Robert. Historical Relation of Ceylon.
  4. Sima Qian. Records of the Grand Historian . Vol. 4.
  5. Pyrotechnic device, Feb 4, 1964, retrieved 2017-02-01
  6. Smoke signal, Nov 28, 1967, retrieved 2017-02-01
  7. "Lewis and Clark Journals, July 20, 1805".
  8. Gusinde 1966:137–139, 186
  9. Itsz 1979:109
  10. "The Patagonian Canoe". Retrieved 2013-02-19.
  11. Extracts from the following book. E. Lucas Bridges: Uttermost Part of the Earth. Indians of Tierra del Fuego. 1949, reprinted by Dover Publications, Inc (New York, 1988).
  12. 1 2 Myers, 1986: 100
  13. 1 2 "Report on Patrol to Lake Mackay Area June/July 1957". National Archives of Australia. Retrieved 2014-01-31.
  14. 1 2 3 4 5 Idriess, Ion L (1953). The Red Chief. ettimprint.
  15. 1 2 Idriess, Ion L (1937). Over the Range. ettimprint.

Related Research Articles

A beacon is an intentionally conspicuous device designed to attract attention to a specific location. A common example is the lighthouse, which draws attention to a fixed point that can be used to navigate around obstacles or into port. More modern examples include a variety of radio beacons that can be read on radio direction finders in all weather, and radar transponders that appear on radar displays.

Digital data Discrete, discontinuous representation of information

Digital data, in information theory and information systems, is information represented as a string of discrete symbols each of which can take on one of only a finite number of values from some alphabet, such as letters or digits. An example is a text document, which consists of a string of alphanumeric characters. The most common form of digital data in modern information systems is binary data, which is represented by a string of binary digits (bits) each of which can have one of two values, either 0 or 1.

Telegraphy Long distance transmission of text

Telegraphy is the long-distance transmission of messages where the sender uses symbolic codes, known to the recipient, rather than a physical exchange of an object bearing the message. Thus flag semaphore is a method of telegraphy, whereas pigeon post is not. Ancient signalling systems, although sometimes quite extensive and sophisticated as in China, were generally not capable of transmitting arbitrary text messages. Possible messages were fixed and predetermined and such systems are thus not true telegraphs.

Message Discrete unit of communication

A message is a discrete unit of communication intended by the source for consumption by some recipient or group of recipients. A message may be delivered by various means, including courier, telegraphy, carrier pigeon and electronic bus. A message can be the content of a broadcast. An interactive exchange of messages forms a conversation.

Chaffing and winnowing is a cryptographic technique to achieve confidentiality without using encryption when sending data over an insecure channel. The name is derived from agriculture: after grain has been harvested and threshed, it remains mixed together with inedible fibrous chaff. The chaff and grain are then separated by winnowing, and the chaff is discarded. The cryptographic technique was conceived by Ron Rivest and published in an on-line article on 18 March 1998. Although it bears similarities to both traditional encryption and steganography, it cannot be classified under either category.

In cryptography and computer security, a man-in-the-middle, monster-in-the-middle, machine-in-the-middle, monkey-in-the-middle, meddler-in-the-middle (MITM) or person-in-the-middle (PITM) attack is a cyberattack where the attacker secretly relays and possibly alters the communications between two parties who believe that they are directly communicating with each other, as the attacker has inserted themselves between the two parties. One example of a MITM attack is active eavesdropping, in which the attacker makes independent connections with the victims and relays messages between them to make them believe they are talking directly to each other over a private connection, when in fact the entire conversation is controlled by the attacker. The attacker must be able to intercept all relevant messages passing between the two victims and inject new ones. This is straightforward in many circumstances; for example, an attacker within the reception range of an unencrypted Wi-Fi access point could insert themselves as a man-in-the-middle. As it aims to circumvent mutual authentication, a MITM attack can succeed only when the attacker impersonates each endpoint sufficiently well to satisfy their expectations. Most cryptographic protocols include some form of endpoint authentication specifically to prevent MITM attacks. For example, TLS can authenticate one or both parties using a mutually trusted certificate authority.

A distress signal, also known as a distress call, is an internationally recognized means for obtaining help. Distress signals are communicated by transmitting radio signals, displaying a visually observable item or illumination, or making a sound audible from a distance.


A wink is a facial expression made by briefly closing one eye. A wink is an informal mode of non-verbal communication usually signaling shared hidden knowledge or intent. However, it is ambiguous by itself and highly dependent upon additional context, without which a wink could become misinterpreted or even nonsensical. For example, in some regions of the world, a wink may be considered rude or offensive. And depending on the relationship of the people involved, a wink could possibly constitute a sexual gesture.

Polybius square Type of code

The Polybius square, also known as the Polybius checkerboard, is a device invented by the ancient Greeks Cleoxenus and Democleitus, and made famous by the historian and scholar Polybius. The device is used for fractionating plaintext characters so that they can be represented by a smaller set of symbols, which is useful for telegraphy, steganography, and cryptography. The device was originally used for fire signalling, allowing for the coded transmission of any message, not just a finite amount of predetermined options as was the convention before.

Drums in communication Drums used for long-distance signalling and communications

Developed and used by cultures living in forested areas, drums served as an early form of long-distance communication, and were used during ceremonial and religious functions.

Two-way radio Radio that can both transmit and receive a signal, used for bidirectional voice communication

A two-way radio is a radio that can both transmit and receive radio waves, unlike a broadcast receiver which only receives content. It is an audio (sound) transceiver, a transmitter and receiver in one unit, used for bidirectional person-to-person voice communication with other users with similar radios. Two-way radios are available in stationary, mobile, and hand-held portable models. Hand-held two-way radios are often called walkie-talkies, handie-talkies or hand-helds. Two-way radios are used by groups of geographically separated people who need to keep in continuous voice communication, such as aircraft pilots and air traffic controllers, ship captains and harbormasters, emergency services personnel like firefighters, police officers, and ambulance paramedics, taxi and delivery services, soldiers and military units, fast food and warehouse employees, and radio amateurs.

A secret broadcast is, simply put, a broadcast that is not for the consumption of the general public. The invention of the wireless was initially greeted as a boon by armies and navies. Units could now be coordinated by nearly instant communications. An adversary could glean valuable and sometimes decisive intelligence from intercepted radio signals:

Selknam people Indigenous people of Tierra del Fuego

The Selk'nam, also known as the Onawo or Ona people, are an indigenous people in the Patagonian region of southern Argentina and Chile, including the Tierra del Fuego islands. They were one of the last native groups in South America to be encountered by migrant Europeans in the late 19th century. In the mid-19th century, there were about 4000 Selk'nam; by 1919 there were 297, and by 1930 just over 100.

Military communications Messages within armed forces

Military communications or military signals involve all aspects of communications, or conveyance of information, by armed forces. Military communications span from pre-history to the present. The earliest military communications were delivered by runners. Later, communications progressed to visual and audible signals, and then advanced into the electronic age. Examples from Jane's Military Communications include text, audio, facsimile, tactical ground-based communications, naval signalling, terrestrial microwave, tropospheric scatter, satellite communications systems and equipment, surveillance and signal analysis, security, direction finding and jamming.

In software architecture, a messaging pattern is an architectural pattern which describes how two different parts of an application, or different systems connect and communicate with each other. There are many aspects to the concept of messaging which can be divided in the following categories: hardware device messaging and software data exchange. Despite the difference in the context, both categories exhibit common traits for data exchange.


Fuegians are the indigenous inhabitants of Tierra del Fuego, at the southern tip of South America. In English, the term originally referred to the Yaghan people of Tierra del Fuego. In Spanish, the term fueguino can refer to any person from the archipelago.

Phryctoria was a semaphore system used in Ancient Greece. The phryctoriae were towers built on selected mountaintops so that one tower (phryctoria) would be visible to the next tower. The towers were used for the transmission of a specific prearranged message. Flames were lit on one tower and then the next tower in succession also lit flames.

Hydraulic telegraph Semaphore systems using water-based mechanisms

A hydraulic telegraph refers to two different semaphore systems involving the use of water-based mechanisms as a telegraph. The earliest one was developed in 4th-century BC Greece, while the other was developed in 19th-century AD Britain. The Greek system was deployed in combination with semaphoric fires, while the latter British system was operated purely by hydraulic fluid pressure.

Semaphore Mechanical apparatus used to send messages

Semaphore is the use of an apparatus to create a visual signal transmitted over distance. A semaphore can be performed with devices including: fire, lights, flags, sunlight and moving arms. Semaphores can be used for telegraphy when arranged in visually connected networks, or for traffic signalling such as in railway systems, or traffic lights in cities.

Lone Signal Crowdfunded project to send interstellar communications to extraterrestrials

Lone Signal was a crowdfunded active SETI project designed to send interstellar messages from Earth to a possible extraterrestrial civilization. Founded by businessman Pierre Fabre and supported by several entrepreneurs, Lone Signal was based at the Jamesburg Earth Station in Carmel, California.