Smoke signal

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

History and usage

In Ancient China, soldiers stationed along the Great Wall would alert each other of impending enemy attack by signaling from tower to tower. In this way, they were able to transmit a message as far away as 750 kilometres (470 mi) in just a few hours.

Polybius, a Greek historian, devised a more complex system of alphabetical smoke signals around 150 BC, 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.

The 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.

Smoke signal (disambiguation)

Smoke signals are a form of visual communication used over long distances.

Smoke Signals may also refer to:

Smoke Signal (film)

Smoke Signal is a 1955 Western film directed by Jerry Hopper and starring Dana Andrews.

References

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