From the Great Wall of China to Ancient Greece, smoke signals were one of the earliest forms of visual communication – a fascinating medium which still lives on in the twenty-first century.
Centuries before mankind could ping news across the planet in a second by smartphone or rely on landmark inventions like radio and the telegraph, smoke signals were the original conduit for long-distance communication.
Traditionally used for important announcements, to warn of approaching danger, or to muster forces, smoke signals were born in Ancient China and then relayed to every continent.
And while technology might have moved on, they haven’t been extinguished: even today, the election of a new pope is announced to millions across the world via coloured smoke plumes, while generations of Boy Scouts continue to fly the flag for the ancient art of the smoke signal.
Smoke signals originated in Ancient China, where they were used by soldiers guarding the Great Wall to warn of invasions by the Xiongnu and Dong Hu peoples over the country’s northern border. When the enemy was spotted, soldiers guarding thousands of beacon towers spaced all along the wall would light fires; in this way word of the impending attack could be passed along its entire 7,300km length, travelling hundreds of kilometres in just a few hours.
Beacon towers relayed ‘all clear’ signals each morning and at nightfall, as well as other crucial tactical information. By night, owing to visibility, torches were used instead of smoke. The number of smoke signals, the colour of the smoke, and the number of times torches were raised or lowered could all convey details about the number of approaching troops.
Fascinatingly, although in ancient and modern literary Chinese the outbreak of war is poetically described as ‘wolf smoke rising around us’ (langyan si qi), it’s likely that the soldiers used vegetation rather than wolf dung (a common myth) to fuel their fires. Later, under the Ming dynasty, saltpeter and sulphur were added to make the smoke more clearly visible.
Even at the start, smoke signals had a tendency to be abused: the fall of the Western Zhou Dynasty has been attributed to the fact that King You of Zhou was given to fooling his warlords with false warning beacons in order to amuse his concubine. When an actual rebellion happened, no one came to his aid – an early predecessor of Aesop’s fable about the boy who cried wolf.
Smoke and mirrors
The Ancient Greeks raised fire signalling to an art via the Polybius square, developed and made famous in the second century BC by the eponymous historian. The device converted plaintext characters into a far smaller set of symbols, allowing the coded transmission of any message, as opposed to the few preset options which had been possible before. Torches were used both to initiate the message, and to signal which row of the square, and then which letter, was intended.
According to legend, the Greeks had mastered smoke signals far earlier: in Æschylus’s celebrated play ‘Agamemnon’, the eponymous king communicates news of the fall of Troy (ca. 1184 BC) to his wife Clytemnestra via beacon fires that contrive to travel across eight mountains in a single night. It’s also claimed that celebrated military strategist Hannibal deployed smoke signals in his defeat of the Gauls while crossing the Alps around 218 BC.
An indigenous art
The indigenous peoples of the Americas would later develop methods of transmitting news which revived this art of the ancients, setting the plains on fire to communicate the presence of their party or their desire to meet with other tribes.
They obtained puffs of smoke by placing blankets or robes over the fire, withdrawing them temporarily, and then putting them back. There were several standard smoke signals: one puff for ‘Attention’; two for ‘All is well’, and three for ‘danger, trouble, need help!’ These would be conveyed by a fire’s placement: halfway up the hill meant no problem, the top meant danger.
Yet such fires could be understood by all who saw them – so various tribes such as the Apache and Navajo also devised their very own set of signals, relying on basic Morse Code-style patterns to hide their intended message from the enemy.
It’s unclear how widespread such smoke-signalling was, but it became fused in the popular imagination with the image of Native Indians, working its way into westerns and even onto a U.S. stamp. Smoke signals became shorthand for cliches of the Native Americans themselves.
Indigenous Australians are meanwhile true masters of fire, having used it as a tool for bushfire management for thousands of years – a practice which many suggest we should look to today. When it came to smoke signals, Aboriginal Australians not only varied the colour and shape of their smoke to carry information but could also use it to denote the names of tribesmen.
An article in the Adelaide-based paper The Advertiser, dated 10 October 1893, and outlining a paper by a certain A. T. Magarey, suggests just how specific these signals could be:
The meanings of spiral coils are curious and some account of them is here given:—Spiral coils of thin pale or dark smoke —Powell’s Creek Tribe.—Native name of the signal ‘Mullagar Winlabardim’ and meaning ‘All about; come quick: plenty of kangaroo.’ Similar coils of dense dark smoke ‘Umbarunnie’ mean ‘Two men come quick; help carry game.’
Such was the local reliance on smoke signals that, when he first discovered Australia’s east coast in 1770, explorer Captain James Cook described the land as ‘a continent of smoke’, noting that ‘we saw smoke by day or fires by night wherever we came’. For Cook, this was a sign of mankind’s sophistication – that the land he had discovered was home to a new race of humanity.
Guarding the flame
Millions of people today tune in to hear the announcement of a new pope – an event which revolves around a temporary chimney atop the Sistine Chapel, site of the all-important smoke signal revealing whether or not the papal conclave has been decisive. This practise is relatively new: Pope Pius X, who died in 1914, declared that ballots to elect a new pope should be burned to preserve secrecy; after his death, cardinals decided that black smoke (‘fumata nera’) should signal an inconclusive vote, and white smoke (‘fumata bianca’) the election of the next pontiff.
Originally the College of Cardinals burned wet straw with the ballots to lend the smoke its white colour, and tarry pitch for black – but the hues were ambiguous, causing confusion. They have now moved on to chemical compounds burned in a second stove and then mixed with that of the burnt ballot papers: a mix of potassium perchlorate, anthracene, and sulphur in the case of black smoke; and potassium chlorate, lactose and rosin – an amber resin – in the case of white smoke.
But the true guardians of the flame are arguably the Boy (and Girl) Scouts of America, for whom fire has long been a preoccupation – unsurprising given their famous motto: ‘Be Prepared’. The 1911 Boy Scout Manual advises lost Boy Scouts to announce their position by firing a gun – but if this doesn’t work to use smoke signals:
If this brings no help, send up a distress signal–that is, make two smoke fires by smothering two bright fires with green leaves and rotten wood, and keep them at least fifty feet apart, or the wind will confuse them. Two shots or two smokes are usually understood to mean ‘I am in trouble.’ Those in camp on seeing this should send up one smoke, which means, ‘Camp is here.’
Smoke signals also live on in the clouds – conveyed through the art of skywriting, whereby one or more aircraft expels smoke during flight, and carves patterns to create messages readable from the ground.
Invented in the early twentieth century, skywriting became a commercial business by the 1930s, used by companies like Pepsi-Cola to reach a mass market. More romantically, smoke signals today are often used to send birthday wishes, or personal messages like proposals. From military strategy to romance, smoke signals have spread a long way from their ancient origins.