« Wind up your laptop | Main | Heat your house with car tyres and earth »

December 23, 2007

Email in the 18th century: the optical telegraph

Copy_optical_telegraph_tower_4 More than 200 years ago it was already possible to send messages throughout Europe and America at the speed of an aeroplane – wireless and without need for electricity.

Email leaves all other communication systems far behind in terms of speed. But the principle of the technology – forwarding coded messages over long distances – is nothing new. It has its origins in the use of plumes of smoke, fire signals and drums, thousands of years before the start of our era. Coded long distance communication also formed the basis of a remarkable but largely forgotten communications network that prepared the arrival of the internet: the optical telegraph.

(Maps and picture : Ecole Centrale de Lyon)

--------------------------------------------------------------------------------------------------------

Every tower had a telegrapher, looking through the telescope at the previous tower in the chain.

--------------------------------------------------------------------------------------------------------

Throughout history, long distance communication was a matter of patience – lots of patience. Postmen have existed longer than humans can write, but the physical transport of spoken or written messages was always limited by the speed of the messenger. Humans or horses can maintain a speed of 5 or 6 kilometres an hour for long distances. If they walk 10 hours a day, the transmission of a message from Paris to Antwerp would take about a week. 

Already in antiquity, post systems were designed that made use of the changing of postmen. In these stations, the message was transferred to another runner or rider, or the horseman could change his horse. These organised systems greatly increased the speed of the postal services. The average speed of a galloping horse is 21 kilometres an hour, which means that the distance in time between Paris and Antwerp could be shortened to a few days. A carrier pigeon was twice as fast, but less reliable. Intercontinental communication was limited to the speed of shipping.

Copy_optical_telegraph_france_2 A chain of towers

Centuries of slow long-distance communications came to an end with the arrival of the telegraph. Most history books start this chapter with the appearance of the electrical telegraph, midway the nineteenth century. However, they skip an important intermediate step. Fifty years earlier (in 1791) the Frenchman Claude Chappe developed the optical telegraph. Thanks to this technology, messages could be transferred very quickly over long distances, without the need for postmen, horses, wires or electricity.

The optical telegraph network consisted of a chain of towers, each placed 5 to 20 kilometres apart from each other. On each of these towers a wooden semaphore and two telescopes were mounted (the telescope was invented in 1600). The semaphore had two signalling arms which each could be placed in seven positions. The wooden post itself could also be turned in 4 positions, so that 196 different positions were possible. Every one of these arrangements corresponded with a code for a letter, a number, a word or (a part of) a sentence.

1,380 kilometres an hour

Every tower had a telegrapher, looking through the telescope at the previous tower in the chain. If the semaphore on that tower was put into a certain position, the telegrapher copied that symbol on his own tower. Next he used the telescope to look at the succeeding tower in the chain, to control if the next telegrapher had copied the symbol correctly. In this way, messages were signed through symbol by symbol from tower to tower. The semaphore was operated by two levers. A telegrapher could reach a speed of 1 to 3 symbols per minute.

The technology today may sound a bit absurd, but in those times the optical telegraph was a genuine revolution. In a few decades, continental networks were built both in
Europe and the United States. The first line was built between Paris and Lille during the French revolution, close to the frontline. It was 230 kilometres long and consisted of 15 semaphores. The very first message – a military victory over the Austrians – was transmitted in less than half an hour. The transmission of 1 symbol from Paris to Lille could happen in ten minutes, which comes down to a speed of 1,380 kilometres an hour. Faster than a modern passenger plane – this was invented only one and a half centuries later.

Copy_optical_telegraph_france2_3From Amsterdam to Venice

The technology expanded very fast. In less than 50 years time the French built a national infrastructure with more than 530 towers and a total length of almost 5,000 kilometres.
Paris was connected to Strasbourg, Amsterdam, Toulon, Perpignan, Lyon, Turin, Milan and Venice. At the beginning of the 19th century, it was possible to wirelessly transmit a short message from Amsterdam to Venice in one hour’s time. A few years before, a messenger on a horse would have needed at least a month’s time to do the same.

The system was copied on a large scale in other countries. Sweden developed a country-wide network, followed by parts of England and North America. A bit later also Spain, Germany and Russia constructed a large optical telegraph infrastructure. Most of these countries devised their own variations on the optical telegraph, using shutters instead of arms for example. Sweden developed a system that was twice as fast, Spain built a telegraph that was windproof. Later the optical telegraph was also put into action in shipping and rail traffic.

A real European network never really existed. The connection between Amsterdam and Venice existed for only a short period. When Napoleon was chased out of the Netherlands, his telegraph network was dismantled. The Spanish, on the other hand, started too late. Their nationwide network was only finished when the technology started to fall into disuse in other countries. The optical telegraph network was solely used for military and national communications, individuals did not have access to it – although it was used for transmitting winning lottery numbers and stock market data. Map : Ecole Centrale de Lyon

Intercontinental communication 

The optical telegraph disappeared as fast as it came. This happened with the arrival of the electrical telegraph, fifty years later. The last optical line in France was stopped in 1853, in Sweden the technology was used up to 1880. The electrical telegraph was not hindered by mist, wind, heavy rainfall or low hanging clouds, and it could also be used at night. Moreover, the electrical telegraph was cheaper than the mechanical variant. Another advantage was that it was much harder to intercept a message – whoever knew the code of the optical telegraph, could decipher the message. The electrical telegraph also made intercontinental communication possible, which was impossible with the optical telegraph (unless you made a large detour via Asia.

The electrical telegraph was the main means of communication for transmitting text messages over long distances for more than 100 years. At first, electrical wires were used; later on radio waves were used to communicate. The first line was built in 1844, the first transatlantic connection was put into use in 1865. The telegraph made use of Morse code, where dots and dashes symbolize letters and numbers.

Not the telephone, nor the railroads, nor radio or television made the telegraph obsolete. The technology only died with the arrival of the fax and the computer networks in the second half of the 20th century. Also in rail-traffic and shipping optical telegraphy was replaced by electronic variants, but in shipping the technology is still used in emergency situations (by means of flags or lamps).

Keyboard

Copy_red_de_telegrafa_ptica_1844185

The electrical telegraph is the immediate predecessor of e-mail and internet. Since the thirties, it was even possible to transmit images. A variant equipped with a keyboard was also developed, so that the technology could be used by people without any knowledge of Morse code. The optical as well as the electrical telegraph are both in essence the same technology as the internet and e-mail.

All these means of communication make use of code language and intermediate stations to transmit information across large distances; the optical telegraph uses visual signs, the electrical telegraph dots and dashes, the internet ones and zeroes. Plumes of smoke and fire signals are also telegraphic systems – in combination with a telescope they would be as efficient as an optical telegraph.  Map: optical telegraph network in Spain, 1844-1857 : Luis Enrique Otero Carvajal

Low-tech internet

Of course, e-mail is much more efficient than the optical telegraph. But that does not alter the fact that the low-tech predecessor of electronic mail more or less obtained the same result without wires or energy, while the internet consists of a cluster of cables and is devouring our energy resources at an ever faster pace.

© Kris De Decker (edited by Vincent Grosjean)h (Artículo en español)f

Comments on the article can be found on Slashdot
--------------------------------------------------------------------------------------------------------

More on Low-tech Magazine :

Sepia2_mg_0768 The digital oubliette : chances are slim your children will be able to enjoy the family photo album when they grow up

A world without trucks : 19th century pneumatic post service was faster than today's couriers

Reinventing the wheel : the story of the motorized monowheel

Why the electric car has no (wireless) future

Satellite navigation in the 18th century : who needs GPS?

Download a classic car

Wind up your laptop : human energy

Main page / Site map / Search / Subscribe to feed or email

--------------------------------------------------------------------------------------------------------

Found

  • Help in case of an atomic bomb attack
    One reason to get down flat is to let the worst of it pass over you (see & read) (Via)
  • Build an electric car
    Retrofitting a 1970s Fiat 500 (read)
  • Minerals
    “Peak oil” is just one of several cases of worldwide peaking and decline of a depletable resource (read)
  • Travelling light
    Airships are one of several green technologies which might be killed by a shortage of materials (read)
  • Farms became factories
    Chemical corporations continue their propaganda efforts to convince farmers that they cannot make a profit without using chemicals, antibiotics, hormones, and genetically manipulated crops and animals (read)
  • Take it easy
    A 0.5 horse power car (see & read)
  • Robot wars
    Airstrikes from unmanned aircraft over Iraq hit record levels in April (read)
  • TV
    A screen that ships without a mouse ships broken (read)
  • Privacy
    How to kill an RFID tag (read)
  • Insurance versus nature
    In the past five years, London councils alone have chopped down almost 40,000 street trees (read)
  • Long-term storage (2)
    How to make a Moleskine notebook (make)
  • Long-term storage
    It only takes five years and archived data is obsolete (read)
  • Monsanto rules (2)
    Genetic modification actually cuts the productivity of crops (read)
  • Monsanto rules (1)
    Intellectual property thuggery is not restricted to the IT and entertainment industries (read)
  • Time is money
    From New York to Los Angeles in 48 hours (read)
  • Solar
    One of oldest forms of energy used by humans -- sunlight concentrated by mirrors -- is poised to make an astonishing comeback (read)
  • Book of the future
    From stone-age tools to space-age computers (see & read)
  • Food crisis
    What level of meat-eating would be sustainable? (read)
  • Green cars (2)
    Cars like the Aptera are severely impeding humanity's faltering steps towards creating a sustainable society (read)
  • Green cars
    From rainforest to rubber plantation (read)
  • Time capsule
    2000 A.D. (see)
  • Time capsule
    2063 A.D. (read)
  • Green buildings (2)
    It takes 90,000 kWh of energy to construct a single family dwelling (read)
  • Green buildings (1)
    Even if 40% of the materials in a new building are recycled, it would take 65 years for a green, energy-efficient new office building to recover the energy lost in demolishing an existing building (read)
  • Flying
    The revival of propeller-driven planes (read)
  • Water
    Low-tech lemonades (make)
  • The front lawn
    What is that chasm between house and street? Why is it there? Or rather, why is nothing there? (read)
  • Ethanol
    The road to hell is paved with good intentions (read)
  • Wheels
    The car of the future (see)
  • Communications
    Build a telegraph (make)
  • Housing
    Build an eco village (make)
  • Wireless
    Mobile phones more dangerous than smoking? (read)
  • Magnetic levitation
    Germany ditches Transrapid project (read)
  • Writing
    Emoticons on paper (see)
  • Trees versus solar
    What happens when one neighbour with solar panels sues another with big, shady trees? (read)
  • Public transport
    A bus to keep pace with other transportation (see)
  • Obsolete skills
    People would actually have to hold what they called Pens or Pencils if they were very old, and put this in contact with paper, which would make marks that they called "writing" (read)
  • The new black
    Clean coal is a combination of two technologies, one of which is expensive and the other completely unproven (read)
  • Bat phones
    The low-tech hearing aid is an update to simply cupping your hand to your ear (see & read)
  • Space travel
    After travelling hundreds of thousands of kilometers, the landing crew of the Apollo 11 lunar mission barely covered an area the size of a football/soccer pitch (see)
  • Food miles
    There is only one way of being sure that you cut down on your carbon emissions when buying food: stop eating meat, milk, butter and cheese (read)


  • StumbleUpon