: The earliest recorded use dates to the 8th century BC. Soldiers along the Great Wall of China used smoke to signal imminent danger or enemy movements.
Report: The History and Application of Smoke Signals The smoke signal is one of the oldest forms of long-distance visual communication, used by diverse cultures throughout history to transmit news, signal danger, or gather people. While often associated with Native American tribes, it has been used by ancient civilizations in China, Greece, and Rome. Historic Use and Origins 1 : Smoke Signal
: Tribes such as the Apache and Coeur d'Alene developed precise signaling methods using damp grass to create thick columns of white smoke. : The earliest recorded use dates to the 8th century BC
Because signals were visible to everyone, including enemies, meanings were often pre-arranged between specific senders and receivers to maintain secrecy. However, several general codes became common: While often associated with Native American tribes, it
: Since the 19th century, the College of Cardinals has used smoke to announce election results: black smoke indicates a failed vote, while white smoke signals a new pope. Core Signaling Language