Hydraulic telegraph: Ancient means of long-distance communication

In the 4th century BC, a Greek named Aeneas invented a hydraulic telegraph that could help people communicate over long distances. The way to make and operate this device is quite simple but brings very high communication efficiency.

Advances in the field of technology have dramatically changed our lives today compared to the distant past. Thanks to modern devices, it is easy for us to communicate with others at long distances, or to communicate with large groups of people. Looking back at ancient civilizations, we'll get a deeper look at the first human method of long-distance communication.

Relief of the hydraulic telegraph by Aeneas.

In 350 BC, Aeneas invented the hydraulic telegraph – a means of communication that quickly conveyed important and detailed information over long distances.

Aeneas was a Greek writer, knowledgeable about military history, strategy, communications. He was one of the first authors to provide guidance on military communications. This discovery is very important in helping to exchange and communicate military tactics and strategies in times of war or when sudden attacks occur.

Before that, Aeneas had been frustrated by the limited methods of communication through torches and beacons. The torches allowed to convey some messages such as warning of danger or announcing that a goal was accomplished, but they could not send messages with clear messages.

Aeneas developed the hydraulic telegraph to overcome these problems. In 'The Histories', the Greek historian Polybius detailed the invention of Aeneas. The hydraulic telegraph structure consists of a large cylindrical water tank and a vertical rod floating above the water. On the bar were pasted pieces of paper with pre-encrypted messages, such as 'cavalry coming in' or 'there is a warship'.

Two telegraphs would be placed at a distance from each other but still within view of the observer, usually on top of a hill. When one side wants to send a message to the other, they will raise the torch. If the torch is seen, the second party also raises the torch to confirm that they are ready to receive the message. At the moment the first sender lowers the torch, both sides will simultaneously turn on the faucet located at the bottom of the container to gradually lower the water level.

When the piece of paper with the message to be conveyed moves to the top edge of the container, the sender of the message will light his torch again, signaling the receiver to turn off the faucet and read the message on the piece of paper. horizontal to the edge of the jar.

For the most complete and accurate information transmission, both parties [sender and receiver] must use vessels of the same size, containing the same volume of water, and bars containing identical messages. The sender and receiver also have to be very precise, starting and stopping the drain at the same time.

Although the construction of the hydraulic telegraph seemed very simple, the invention was a significant advance in ancient communication technology, allowing messages to be sent over long distances. In the event of an enemy entering or approaching, they will only see the light of the signal torch and cannot intercept the message in any way.

This is also a major step forward in military strategy. During the First Punic War (264–241 BC), messages sent from Sicily to Carthage via a hydraulic telegraph system helped the Roman army to win a great victory.

Through hydraulic telegraphy, groups of soldiers could communicate specific messages to each other, as well as receive intelligence from the population to better prepare for potential enemy invasions by land. or by sea.

Over time, this first form of long-distance communication gradually improved, paving the way for modern forms of communication to become widely used.

By the 19th century, English civil engineer Francis Whishaw had developed a new type of hydraulic telegraph, operated entirely by fluid pressure. It has a similar structure to Aeneas' design, but Whishaw has used an additional pipe filled with water to connect the transmitter and receiver [instead of using the torch signal as before]. The change in pressure at the transmitter will lead to a change in the water level at the receiver, and the observer can read the message to be conveyed written on the piece of paper.

The limitation of this device is that it cannot operate in environments where the temperature is below 0 degrees Celsius, because the water in the pipeline may freeze. This is the main reason why Whishaw's device has never been used in practice, aside from testing at very short distances.

In 1835, Breese Morse successfully built a telegraph that used electrical pulses to transmit coded messages over wires or radio waves. The device works by Morse code, where each letter and number is represented as dots (dot) and dashes (dash). The sender of the message needs to first encrypt the text message in Morse code. This code is then converted into electrical impulses through telegraph keys that move up and down to close or break the electrical circuit between [the transmitter's] battery and the receiver. The signal travels in the conductor as a series of electrical impulses. Finally, the receiver on the other end of the line converts the electrical pulse into the same dots and dashes as it was originally meant to be understood by the receiver.

Morse's telegraph was later widely adopted for a variety of reasons, the most notable of which were its simplicity of operation and relatively low manufacturing cost. Over time, the Morse code he developed gradually became the primary language of telegraphs around the world.

During the 20th century, telegraph technology was gradually replaced by other low-cost long-distance communication services, such as telephone, fax, and email.