Amazing Roman Inventions That Prove They Were So Close to an Industrial Revolution
I have long had a fascination for both history and engineering. Of all the societies that came before, the ones I’ve admired the most have always been those that made the most technological progress. Chief among those are the civilizations of Mesopotamia, Ancient Egypt and Ancient Romans. Whenever I think about the great inventions that ancient people came up with, I always wonder why they didn’t take it one step further. I often find it tragic that these peoples came so close to some engineering breakthroughs, yet the logical evolution of the tools they had never materialized. In this post, I’ll focus on some truly amazing Roman inventions that could have revolutionized their society.
When looking at these inventions, it’s tempting to think that these ancient people were somehow less intelligent than us, because we eventually figured things out, but not them. One thing to keep in mind is that progress is often brought to us as a necessity, by limitations that need to be overcome to reach our goals. I’m sure Roman inventors loved to fantasize about the future, I’m sure that they thought of new concepts all the time that they simply didn’t have the means to achieve technologically. After all, the earliest known science fiction work was by a Roman, a novel in which people sail to the Moon! Just like we’ve been dreaming about flying cars for decades, I’m sure Romans were also thinking about flying or instant communication. Maybe future humans will reflect on us and think we were dumb not to have flying cars, but to us, beyond the cool factor, flying cars don’t add anything to our society for many reasons. We already have cheap and easy ways to travel and our entire infrastructure is built around the car. Flying cars are simply not worth it.
I think that when looking at driving factors in Roman technology evolution, we can ask one really simple question to understand why machines didn’t take over their world. Could a slave have done the same job with comparable speed and quality? If the answer is yes, then you don’t need a new invention, you just need to go to the slave market and buy a slave or two. The city of Rome itself was made up of 30% slaves. Just think how easy whatever work you need to do is when it’s someone else doing all the hard work. Some Roman Senators had hundreds of slaves, and at this point, it’s probably worth it to get an extra one just to figure out what work the others should do.
Firefighting water pump
I think the main takeaway here is the pure quality of the engineering. They could cast bronze pieces with very tight tolerances. These pieces had to slide against one another and rotate about one another without leaking. The ingenuity of the mechanism is also very interesting. In order to provide an uninterrupted flow of water, two pistons were used, which are connected to a single chamber. In this chamber, a valve alternates the flow between the two pistons. While one piston pushes water up to the nozzle, the other draws water from the source. A simple translational movement was converted into uninterrupted water flow.
It makes you wonder what other kind of hydraulic machines they could have developed. Specifically, they could have reversed the principle here and used hydraulic pressure to achieve mechanical work. Let’s estimate the properties of this pump. Given our main principle, the reason this machine exists is because it did something no one could achieve. This particular machine was used to pump water out of its nozzle. For that Roman pump to be useful, it would need to be better than a human or several humans at throwing water. Not only throwing water, but getting water to where a human could not go. So theoretically, this machine would have needed to throw water at a certain distance or height, which could not have been reached by a human with a bucket.
From measuring pixels on that detailed picture, and knowing that the width of the machine is 43 cm, we get that the nozzle opening is about 0.88 cm, so let’s say 1 cm to make everything easy. Given ballistics calculations, reaching an apogee of 5 meters, at 5 meters distance requires 10.2m/s of jet velocity. From this, we can estimate a flow of around 600–800 ml/s, which is not a lot if you ask me. You are not going to extinguish big fires with that, but keep in mind that it’s still much better than a modern water pressure fire extinguisher, which have a flow rate of only about 172 ml/s.
A relationship exists between pressure and velocity at two points in a fluid system.
From our knowledge of the flow rate and the dimension of the piston, we can deduct the velocity at the piston. Knowing that the water jet leaves the system at atmospheric pressure and at 10.2m/s, we can calculate the internal pressure of the system at the piston, which should be approximately 1.5 bar.
That may not be very impressive, but hydraulic machine can multiply your work much more easily than a simple lever can. For instance, a decent hydraulic jack could have easily been constructed from slightly modifying this very water pump. It is already comprised of two pistons, actioned by a lever. By simply closing the nozzle, and changing the size of one of the pistons, you could have a machine that greatly increases your work. For instance, if we made one of the cylinders to be about 80 cm in diameter, it could be used to lift 7 tons, over 1 cm without modifying the rest of the machine, at an operating pressure of 1.5 bar. That’s 7 tons per operator! Now imagine what you could achieve with a hundred of these in the same place. An industrial revolution requires the multiplication of a worker’s productive output and this machine was very close to achieving exactly that.
Here’s a treat, someone making a jack from PVC piping. Now imagine if those were bronze and tell me what Romans could have done with it.
Massive water pump
Now this one is pretty simple, but it may not be fully explained from the caption or image. It’s a water wheel found inside an ancient Roman mine shaft in Spain. As Romans were digging for silver and copper and needed a way of disposing of toxic ground water in the shafts and galleries they were digging, they developed these systems of wheels. Wheels were driven by humans and sent water to a higher level where another wheel could pump it higher. Sixteen such wheels were found in the same shaft that provided a vertical lift capability of 30 meters!
What’s cool here is that Romans only build relatively small tunnels, enough for a human to go through but no more. So it means they had to send the wheels in parts and assemble them in these 3 meter high chambers.
Roman digging operations were impressive and there was nothing getting in the way of them getting to their resources, not even toxic water 30 meters below ground.
The Aqueduct of the Gier
Roman aqueducts are marvels in an of themselves. They traversed complex landscapes and brought drinking water to millions of Romans. They even built bridges, up to 50m high, just to cross other rivers with their man-made one. Their aqueducts could traverse hundreds of kilometers of terrain, losing only a few meters of height overall. They dug tunnels through mountains, sometimes from both sides and meeting in the middle, once again keeping that incredible accuracy needed for such a use case.
Although all of that is impressive, what I want to talk about is a much more complex feat of engineering that shows how well the romans understood hydraulics. Typically, Roman aqueducts were a simple covered canal running on top of some arches, bringing the water forward by a minimal inclination. The water was not under any kind of pressure, it was simply moved via gravity, an artificial river if you like. The path an aqueduct took was usually the one of least resistance. Romans would follow the contours of natural obstacles, to keep the inclination they needed for the whole thing to work.
But what happens when the water you need is far away, behind a mountain? Well that’s easy enough, just dig a tunnel through the mountain, and keep the right inclination. But what happens when there are several mountains and valleys to cross? Specifically, what happens if the water level needed is higher than the highest structure you can build from the bottom of the valley? You build an inverted siphon, or four!
Here is what the Roman came up with to solve this problem. They built two reservoirs, one on each side of the valley they wanted to cross. Then, they connected both reservoirs with pipes. If the downstream reservoir is lower than the upstream reservoir, the water will naturally flow to the lowest point. To me, the mind-blowing part is that the difference in height between the top reservoir and the bottom of the valley, where the pipes were running on a bridge of their own. One of the siphons had well over 100 meters of water head. That translates to roughly 10 bars (10 atmospheres) of pressure in the lower pipes!
What’s really cool as well is that these pipes weren’t some small caliber, they were nearly 30 cm in diameter, comparable to modern pipes you’d find in a city’s water distribution system today. And it wasn’t just one pipe, they had ten to twenty pipes running in parallel. To make sure that the pipes could withstand these immense pressures, they soldered pipe sections in series and encased them in mortar. What’s crazy is that for this whole system to work, there would have to be precisely zero leakage, anywhere in the pipes. Otherwise, the pressure could not be great enough to reach the downstream basin. The downstream basin would also be leaking water backwards. Talk about six sigma. It’s a mystery to me how you would even repair such a thing if it started leaking. I suppose you can plug the broken pipe from one end, let the water leak out of the pipe and pour some more mortar over the leaking area.
But regardless, one marvels at the idea of 10 bars of pressure traversing pipes over several kilometers. Had they wanted to build some high powered hydraulic mill, this sort of engineering would have come really useful.
The Roman Hodometer
The Hodometer, a surveying tool used to calculate distances. It may seem pretty simple, but it actually involves a leap in how engineering and science is performed. This, believe it or not, is a primitive computer. It receives an input from some sensor (the wheel) and transforms it to be displayed to a user (the dial). It converts a great length of basically any shape to be human-readable and accurate.
Just look at this device and tell me what happens if instead of pushing it along the road and reading the dial, you instead turn the dial. Congrats, you’ve just created a basic human powered vehicle. Traction with the ground and friction within the mechanism may have been a slight issue in order to actually move stuff or people along, but tell me no one ever tried spinning the gear and see the cart move along.
Conclusion
Now, there are so many I’ve missed, so there will be a second post about these. I’m thinking of Romans digging long tunnels from both ends and meeting in the middle without any sort of modern measuring equipment. The Roman water organ, a music instrument that’s basically a very primitive user interface. The sculpture copying machine used to make copies from Greek masterpieces. Cranes, massive cranes… A Roman multitool, some surgical equipment… There is just so much more to explore. I hope you enjoyed!
