Before the Internet - bonfires and optical telegraph

History shows that information is much more important than the strength of the army. Napoleon lost at Waterloo because of lack of full knowledge, and Vlad the Impaler chased Turkish troops around his territory until they got tired and ordered the retreat. The world would probably look different if during the Polish-Russian War the 4th Army heard the order to join the attack and did not continue towards Toruń. The first one to learn about the crash, war or any other event reflecting on the markets also won. Information is power and it has always been so.

However, there has always been a problem with the way in which it is communicated. Efficient communication allowed people to hunt for much larger mammoths and was the driving force behind language development. However, there were limitations. The range of human screaming is about 200 meters, but in the battle hustle and bustle it drops even to several meters. On top of that, there is a problem with interference. As far as we can hear the sound, understanding what the sender had to say to us will be troublesome.

People have been aware of this for a long time - hence the use of horns, flags, and runners on the battlefields. Sun Zi described communication in the army as such:

Because they can't hear each other, they have drums and gongs. Because they can't see each other, they have flags and pennants. Drums, gongs, flags and pennants are for efficient communication. When people are united, the brave won't go into battle alone, and the fearful won't go back alone.

But these solutions work well in case of "small" battles - several thousands of soldiers fight as many as one side will let go, throw themselves to escape, and allow to be murdered. More bold plans require much better planning and sequence of actions.

Let us imagine such a situation: The enemy wants to invade our area with the help of a boat. However, he has too few of them to cross all the troops at once. So he descends part of the army and comes back for reinforcements. Our fleet is too weak to attack loaded ships, but empty is different. However, the problem is time. We find out about the arrival of the enemy immediately, but before our ships receive this information, the enemy will be halfway home. In order to carry out the operation efficiently, it would be necessary to send them immediately after the attack, to get them before they return.

Such information must therefore travel a distance of a few dozen or so kilometres within a few minutes at the most. Not to be done for a man or a horse. And then the fire goes all white. The general agrees with the fleet commander that as soon as the first wave arrives, he will light a fire, which will be a signal for him to go with the fleet to meet the enemy. In this way, the ships will be lost, and the invasion will end before it begins.

And so, the first "Telegraph" was just the bonfires. They allowed to send information even for a dozen or so kilometers, and if many nodes were used - even further. However, they had a big flaw, allowing only for 2 states. Yes/No. How to say by means of a bonfire that there is a plague in a given city or the guard suddenly rebelled? How to send a message about grain prices on the market by means of a bonfire? It is not possible. Life is complicated and you can't predict everything.

Ancient people were aware of this and already in the IV century BC came up with the idea of using a water clock. It worked like this: a set of glass vessels with holes on the bottom secured with a cork was prepared beforehand. A cylinder or a plaque with marked levels was placed in both of them. The set prepared in this way was placed on both stations. Different levels could be marked on the rollers. Let's say that it was a daily report about the condition of the city. On the cylinders there was information such as whether everything was all right, send us meals, we need water, we sent a messenger. Of course, there could also be letters, but such communication required a lot of time and skill.

So a different solution was proposed. Polybius created a system that used two rows of five torches each. The first row indicated the line and the second row indicated the column. Thanks to that it was possible to send up to 25 characters, which is of course sufficient number to send each letter of the Greek alphabet and a space between words. This solution was much faster and allowed more information to be sent than previous systems. Unfortunately, it was communication over quite short distances and required a large network of nodes to work efficiently. These drawbacks were not eliminated until the invention of the electric telegraph.

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Ancient antiquity was in decline and we waited for the next breakthrough in communication until the beginning of the 17th century, when Francis Bacon developed a special code using only 2 letters, A and B, or, if you prefer, 2 changes. In order to express the 32 characters, each sign had to be assigned a 5-element system of binary values. It looks as follows:

A = aaaaa
B = aaaab
C = aaaba
D = aaabb
E = aabaa
F = aabab
G = aabba
H = aabbb
I/J = abaaa
K = abaab
L = ababa
M = ababb
N = abbaa
O = abbab
P = abbba
Q = abbbb
R = baaaa
S = baaab
T = baaba
U/V = baabb
W = babaa
X = babab
Y = babba
Z = babbb

Fortunately, shortly after the invention of the cipher, a telescope was discovered. This device made it possible not only to look at the stars, but also to see what was happening in the neighbouring village. And theoretically it was the moment when the building of a semaphore network in Europe could begin. However, this did not happen. I do not want to discuss the causes here, because this is a subject for historians. Nobody was interested in the first semaphores, only in 1792, i.e. almost 200 years after the creation of the Bacon code, the first real-life network appeared.

Frenchman Claude Chappe developed and raised funds for an optical telegraph line from Lille to Paris. The length was 200 kilometres and consisted of 15 stations. The first message sent to Paris was that there was a reflection of one of the cities. The message arrived in less than an hour, not a few days. The system proved its worth and was successfully used by Napoleon during the war.

Network of semaphores in France By Jeunamateur - Own work d'après "La télégraphie Chappe", FNHAR, 1993, CC BY-SA 3.0, link

The semaphore itself was an interesting construction. It was based on a tower on which there were two black arms, capable of taking 7 different positions, and a transverse beam which could be set in 4 different positions.

Semaphore tower

The total possible number of symbols was 196 (7x7x4). It...it was too complicated a system. Yes, the line was very fast - about 30-40 minutes for a typical message, but it experienced a lot of errors and depended on visibility.

Character encoding By Patrick87 - Own work, CC BY-SA 3.0, Link

A similar system was developed in England, but it was slightly more complicated, but at the same time simpler to use. It was based on a board with six diaphragms. The arrangement of the six diaphragms defined a sign. A total of 64 different signals could be transmitted in quite a short time. It was also easier to use, because the transmission and reception was not based on the position of the arms, but on whether the diaphragm was open or not. However, Murray's diaphragm system was abandoned in favour of the more French Popham System.

Murray's Semaphore

It is interesting that the longest network of optical telegraphs in the world existed in the Russian Partition of Poland. The Warsaw-Piotrograd line had 149 stations and employed nearly two thousand people. The system itself was purchased for 120 thousand roubles - a huge amount (a small farm cost ~200 roubles) from France. However, the Russians transformed it into a much simpler one, using a 5 signal character coding system. The map is available here

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The telegraph was an extension of the Tsar's hand to rule over the unruly Poles. It operated from the end of 1839 until around 1854, when the construction of the electric telegraph was started.

I also recommend that you review this film from the Khan Academy

Sources:
https://wynalazki.andrej.edu.pl/index.php/wynalazki/36-t/610-telegraf-op
http://lopacinski.com/wordpress/?page_id=39
https://en.wikipedia.org/wiki/Bacon%27s_cipher
https://en.wikipedia.org/wiki/Polybius_square
https://en.wikipedia.org/wiki/Semaphore_telegraph
https://fr.wikipedia.org/wiki/T%C3%A9l%C3%A9graphe_Chappe