Heron of Alexandria created over a startling 80 inventions during his lifetime, and most of them relied on the properties of air and water.


One of the most fascinating? The first ever vending machine, created in the first century C.E.

This device was designed to prevent temple denizens from taking more holy water than they had purchased. Today, we use vending machines to acquire a never ending supply of mid-afternoon snacks, while Heron's holy water device along with several other "miraculous" inventions still amaze two-thousand years later.


Changing the world of math

A professor and one of the foremost Greek inventors of his era, Heron Alexandrinus (often referred to as Hero) spent his days teaching at the Museum in Alexandria, home to the Library at Alexandria, around 60 C.E.

Heron excelled in mathematics and engineering, creating of one of the first (if not the first) steam engines, the aeolipile. Heron also devised a simple method of iteratively solving the square root of any number using only division and addition, as well as fostering the concept of i, the square root of -1 that plagues many equations.

Stealing holy water

Heron created the first vending machine not out of curiosity, but to stop temple thievery. Patrons of temples commonly took more holy water with them than they paid for — an early failure of the honor system.


To combat this, Heron created the first vending machine, that dispensed water blessed by the officials of the temple. By positioning a lever in the path of an external coin slot, a coin placed by a temple goer would rest against the lever, balancing on the lever until the coin eventually fell off. While the coin applied pressure on the lever, the holy water pours forth from an opened spout. Once the coin falls away, however, a counterweight is released by the movement of the lever and the water spout closes. A simple design, but it made sure no one took more than their allotted share of holy water.

Heron ventured away from holy water with another invention, the bottomless wine glass. An opening in a goblet connected to a supply of wine allowed for a constant level of wine to be kept in a glass. This invention, however, is not applicable in day to day life, as the glass had to stay connected to a wine supply through a series of tubes. Not quite portable, but it did provide for a potable, ever present supply of wine.


Creating "miracles"

Seven of Heron's books exist today, including the tome Automata, which survived the centuries through translation into Arabic. Automata is an interesting collection, a work detailing how to construct "miracles" to bewilder and astonish temple goers. One of these devices automatically opened doors in temples by lighting a fire.


When lit, the fire would increase the temperature of the room. Temperature positively affects pressure, causing a slight increase in the pressure in the room as the fire burned. As the pressure increased, a water placed in a bowl set in the room would flow into a container, with the container initiating a series of levers and pulleys that opened a temple door. It is unknown if any temple actually used this system, but you can see an animation of the steps above.

One of Heron's more bizarre creations consisted of a large device capable of playing a ten minute theater routine. Heron's Theatre Automat used of a system of ropes, knots, and iron balls dropped on drums to produce a thunderous sound. Heron also created a cart that would roll itself in front of an audience and perform.


Several enamored individuals have attempted to re-create Heron's plans, with a 2005 exhibition in Dublin recreating Heron's Theatre Automat, and most engineering students take a shot at re-creating one of Heron's simpler inventions in an undergraduate lab. If you would like to read some of Heron's work, a translation of his treatise Pneumatica is available for free courtesy of the University of Rochester.



The top image is of a "take home" holy water dispenser at St Teresa's in Dublin, with the photo from Kaihsu Tai/CC. Images courtesy of the University of Iowa and animated gif courtesy of Michael Lahanas. Sources linked within the article.