The Hydraulic Telegraph: The First Data Network All The Way From Ancient Greece!

When we think about data networks and systems that use mechanical mechanisms to send data across a distance, we think about this concept as a pretty modern one that only existed as a practical idea in the late 1900s. However, what if I told you that one of the earliest data networks to exist predated the modern internet as we know it? Heck, this ancient data network predates modern digital computers and analog computer systems. The modern electric telegraph is still younger than this particular early data network and most mechanical computers have not been around as long as this old-school data network. And when I say old-school, I mean truly old-school, as this data network was around before the Medieval Times and was developed by one of the oldest civilizations in written history.

There is an ancient device known as the hydraulic telegraph. This particular device was created to use water and mechanical devices in order to send information over long distances. The earliest version of this creation was produced back around 350 BCE by an early inventor and ancient Greek writer by the name of Aeneas Tacticus. It was produced by Tacticus as a device to be used for some long-form data communications during wartime & includes a very complicated system. The telegram worked by having identical containers on separate hills that are not connected to one another with each container being filled with water & having a vertical rod floating within both containers. The rods would have a bunch of predetermined codes put on them at various points along these poles. There would be a spigot at the bottom of these containers and water could be drained out of the device until a desired code was reached. Using a torch or signal, the person sending the code would be able to indicate how long it takes for the water to drain out to the desired code, allowing the receiver to know what signal/code is being communicated.

How these particular telegraph devices work is even explained by the Greek historian Polybius in his book The Histories:

Then we are to fill the vessels with water and put on the corks with the rods in them and allow the water to flow through the two apertures. When this is done it is evident that, the conditions being precisely similar, in proportion as the water escapes the two corks will sink and the rods will disappear into the vessels. When by experiment it is seen that the rapidity of escape is in both cases the same, the vessels are to be conveyed to the places in which both parties are to look after the signals and deposited there. Now whenever any of the contingencies written on the rods occurs he tells us to raise a torch and to wait until the corresponding party raises another. When both the torches are clearly visible the signaler is to lower his torch and at once allow the water to escape through the aperture. Whenever, as the corks sink, the contingency you wish to communicate reaches the mouth of the vessel he tells the signaler to raise his torch and the receivers of the signal are to stop the aperture at once and to note which of the messages written on the rods is at the mouth of the vessel. This will be the message delivered, if the apparatus works at the same pace in both cases.

What is so important about these primitive methods of sending data? Well, while it was limited in codes, it was a great early attempt at long-range telegraphic communication. It came as an early telegraph system that even comes before mechanical optical telegraphs and even inspired a British version that, while never made commercially available, was developed in 1838 by British civil engineer Francis Whishaw using pipes and more modern mechanical pressure systems. All of this came before and helped to inspire, the electric telegraphs that would -eventually - become the basis for the electric systems of communication we use today for the modern internet. So, to put a long story short, you better thank the Greeks and their system of sending codes long distances using containers and water for the modern communications that we get to enjoy today!