Heron of Alexandria

If I asked you when steam power was invented, what would you guess?

If you’re like most educated folks I know, you’ll probably go to the Victorian era, or maybe a little earlier… something about someone named Watts, maybe?

Now, what if I told you that a Greek polymath named Heron of Alexandria designed the first known device to transform steam into rotary motion, and that he did this 2000 years ago?

That’s right: around the same time Rome was transitioning from republic to empire, the intellectual capitol of the world had shifted from Athens to Alexandria. This time was a golden age for innovative thinking, as ideas from all over the known world constantly butted up against one another.

Dynamic and cosmopolitan, Alexandria was a vibrant hub that attracted scholars and inventors from across the Mediterranean world and beyond. It was the Silicon Valley of its day, with lots of little idea factories.

Greek philosophy met directly with Egyptian mathematics and construction. Babylonian astronomy and Mesopotamian water management introduced itself to Roman engineers and philosophers. This swirl of cultural influences was like nothing else the world had seen up to this point.

The Library of Alexandria came to represent all of this knowledge, and scholars of the city had access to the internet of the day, while few alive in the world at the time would ever be exposed to the ideas in the countless books.

Inside of this culture, a curious and innovative mind like Heron’s could really thrive.

Heron is sometimes considered the greatest experimenter of antiquity, and I tend to agree with this assessment. Besides very practical devices that would help get work done right now, like the force-pump that’s used in today’s fire engines, Heron came up with some wild ideas that were literal millennia ahead of his time.

Heron's Fountain was a self-replenishing fountain that seemed like magic. It used the principles of air pressure and displacement to create a continuous display of water flowing upwards.

Speaking of magic, Heron designed (and probably made) automata, or objects that seemed to operate all by themselves. One of these was a kind of self-driving car—a four-wheeled cart that could move in pre-programmed patterns by utilizing a complex system of ropes, winches, and pulleys connected to falling weights.

As mind-blowing as these automata were, the proto-steam-engine might be the most impressive thing Heron invented.

This was a simple (but ingenious) design that demonstrated that steam could be used to power things. 1600 years later, Thomas Newcomen and James Watt would build on the concepts Heron proved possible, designing the modern steam engine and launching the industrial revolution.

The Aeolipile consisted of a hollow sphere mounted on a pair of hollow tubes. Water was poured into the sphere, and then it was heated, turning the water into steam. The steam escaped from the sphere through bent tubes projecting from its equator, creating a strong force that could make the sphere spin around.

It looked something like this:

Although it wasn’t powerful enough for any practical purpose in its time, the Aeolipile demonstrated the potential of steam power and had a significant impact on later inventions.

Human innovation is timeless and unceasing, but there are moments and places where ideas seem to spring forth from nowhere. Golden ages of thought have generally been centered around a city or region, and Alexandria at the time of Heron was one of these hotbeds of innovation, seen only a handful of times in human history.

Heron's work reminds us how important cross-pollination of ideas is. Instead of the lone genius working alone, inventors need to be exposed to lots of diverse ways of seeing the world, and a multitude of other brilliant ideas.

Are there some other ancient inventors or innovators that come to mind when you read about Heron? Let’s talk about them today.