Inventions by Hero of Alexandria

The best-known works by Hero of Alexandria are his Pneumatica and Mechanica in which he described how “Automata” actually works. “Automata” is a Greek word meaning as much as “self-moving”, “self-acting” or “self-willed” which is familiar in our modern world. It may be debated whether the inventions were truly his or if he collected them from other sources available at the Library of Alexandria.  

[Reconstruction inside of Alexandria's Library]

Hero lived in the 1^st century BC, and his Pneumatica was widely read far into the Middle Ages. More than 100 manuscripts have survived, illustrating how ancient texts can live a long life. The earliest surviving copy is kept in the Bibliotheca Marciana in Venice, Italy, and dates from the 13^th century, i.e., 1400 years after it was initially written! 

The inventor’s Mechanica has survived thanks to one single Arabic translation made between 862 and 866 AD, preserved at the Library of Leiden University, the Netherlands. 

His most striking invention, in my eyes, is his steam engine, which I already developed in a separate post, A steam engine in antiquity. 

Another of his inventions is a coin-operated dispenser for Holy Water in Egyptian temples. Worshippers who visited the temple needed this water for their ritual washing. Dropping a coin into the slot of the dispenser would set a chain reaction into motion. The weight of the coin would tilt a metal lever which would open a valve through which the water flowed into the cup held by the worshiper. As the coin slipped off the lever, the valve was closed. This invention eventually led to the modern vending machine. 

Hero took his ingenuity one step further when he conceived a series of mechanisms for the Greek theater. He orchestrated a mechanical puppet show using a system of ropes, knots, and simple machines operated by a rotating cylindrical cogwheel. To add the sound of thunder, he used metal balls released at timed intervals onto a hidden drum. 

Another marvel Hero described in detail is the automatic temple door opener (see: Automatic doors, a 2,000-year-old invention), another way for the priests to collect money. 

He also invented the first wind-powered organ using a small wind wheel, probably not unlike the windmills used by the early modern colonists in Australia and the American Far West. The wind wheel powered a piston and forced air through the organ pipes creating sounds resembling a flute.

This mechanism includes the ‘hydraulis,’ which first appeared in Alexandria also, said to have been built by Ctesibius. It was operated by compressed air channeled through a container of water to equalize the pressure. A row of pipes of different lengths produced the sound. More control was acquired with the keyboard-wind instrument as replicated at the Museum of Dion, Greece (see: Close encounter with an ancient Water-Organ). 

I’d like to pick out one more of Hero's inventions from a list that may have counted up to 80, the syringe. The device is much larger than the one we know today since its purpose was entirely different. It was used to control the delivery of air or fluid with precision. Yet the principle of the antique version is the same: the plunger forced the liquid or air out in a controllable quantity. Something to remember next time we get an injection!

We will never know if the concept of creating a center of knowledge in Alexandria was Alexander’s idea or a later addition by Ptolemy. In my opinion, the concept was too vast for Ptolemy while it would perfectly fit Alexander’s thrive to melt East and West together as initiated at the Susa Wedding. 

We cannot imagine the impact of the Museum of Alexandria and its Library on the world’s history. Philosophers, mathematicians, botanists, writers, poets, historians, physicists, anatomists, astrologists, investors, and engineers from all over the then-known world would mingle and exchange their scholarship and wisdom. No other city in the world has ever reunited so many bright minds, not even in the Renaissance. Today’s digital world is the first to come close to attaining this level of universality.

Alexandria: Past Futures

Bozar in Brussels is presently hosting an exhibition about Alexandria that will run until January 8, 2023. 

The event covers the period from the foundation of the city by Alexander the Great in 333 BC to the 4^th century AD. After that date, Alexandria lived as a small fishing port, slowly sinking into the Mediterranean Sea. At the same time, the proud remains of the city disappeared under layers of sand and dust. 

Occasional Byzantine and Arabic travelers left us sketchy descriptions of the scant remains and the monuments built on top of the antique ruins. 

When Napoleon landed here in 1798, only a few columns hinted at earlier streets, and obelisks stood as reminiscent city markers. During this campaign, the Stone of Rosetta was discovered, a three-lingual decree issued in 196 BC, i.e., during Ptolemaic rule. The first two texts were written in ancient Egyptian, using hieroglyphs and Demotic script; the bottom section repeated the text in ancient Greek. We have to thank the Frenchman Champollion for deciphering the hitherto secret hieroglyphic signs, disclosing the history of a world that had been hidden for almost 13 centuries. 

The exhibition opens with a lovely bronze statuette of Alexander the Great, initially on horseback. I know the piece from many photographs, but this is the first time I have seen it on display. It is on loan from the Fondation Gandur pour l'Art, Geneva, and has been dated to Ptolemaic times between the 3^rd and the 1^st century BC. In my eyes, it is worth the visit by itself! 

Central to this exhibition is the Pharos, one of the Seven Wonders of the Ancient World. There is an interesting cardboard model made in the 19^th or 20^th century, but also two color drawings presented in a manuscript from the 16^th century by Muhammad Ibn-Abdal-Rahim kept at the Bibliothèque Nationale de France in Paris. The famous lighthouse is evidently pictured on several coins, like the beautiful example of Hadrian. On the reverse, Isis is holding a sail in front of the lighthouse (Bibliothèque Nationale de France, Paris, départment des Monnaies). 

A separate showcase is occupied by a delegation of the Ptolemaic dynasty. We recognize Berenice II, 246-222 BC, from Hermopolis Magna (Musée de Mariemont); a limestone Ptolemy III, 3^rd century BC (Antikensammlung in Kassel); and a well-polished basalt head of a Roman Emperor, 30 BC-68 AD (Louvre). 

Close by, there is the marble head of a charming Berenice II from the 3^rd century BC that displays traces of paint (Kassel Antikensammlung). She is set next to a Colossal limestone Royal with his typical Egyptian headdress, but with a face executed in pure Hellenistic style. A proof, if necessary, of the blending of both cultures. The Royal has been dated 305-222 BC (Vienna, Kunsthistorisches Museum). 

Nothing is left of Alexandria’s Museum or its precious Library, meant to be a university and research center where great minds met and exchanged their knowledge. The list of philosophers, scientists, mathematicians, astronomers, geographers, physicians, botanists, and zoologists seems endless. 

For example, the exhibition highlights Ctesibius of Alexandria, who invented all kinds of complicated machines, including a water clock and a fire engine. 

Alexandria was famous for its high-standard craftsmen whose art showed in everyday objects such as those exhibited here and dating from the 1^st and 4^th century AD: a glass aryballos, a beaker, a fial, a few drinking glasses, and a finely polished onyx skyphos. Most remarkable, however, were the fascinating mosaics using tiny tesserae, making the scene look like a painting! The originals were apparently too delicate to be moved, but the visitor is treated to an excellent photograph instead. It is worthwhile to take a very close look! 

The Egyptian goddess Isis clearly lives on into Roman times, often assimilated to Aphrodite. Two remarkable original frescos from the 1^st century AD found in Pompeii illustrate her importance (National Archaeological Museum of Naples). 

The exhibition ends with a huge photograph called The Flood of the Nile, found in Palestrina, north of Rome. It is one of the largest Hellenistic mosaics from the 1^st century BC that once adorned the floor of a building on the Forum. It is a bird's-eye view of Egypt with illustrations of its natural history. The top of the picture corresponds to the sources of the Nile in Ethiopia and Nubia, populated by wild animals with their names written in Greek. At the center, we see a succession of temples in Pharaonic and Graeco-Roman traditions. The bottom covers the busy Nile delta and harbor. The original mosaic is home to the National Archaeological Museum of Palestrina. It perfectly illustrates the excellent craftsmanship of Alexandrian artists working in Italy. 

Alexandria: Past Futures presents some 200 artifacts, which for the greater part come from lesser-known museums like that of Mariemont in Belgium, the Kassel Antikensammlung in Germany, the Kunsthistorisches Museum in Vienna, the Fondation Gandur pour l'Art of Geneva in Switzerland, the Bibliothèque Nationale de France in Paris, the National Archaeological Museum of Palestrina in Italy, and several others.

Alexandria, the first Renaissance

The term Hellenism is often interchanged with Greek, especially in art. Classical Greek art almost unnoticeably merged with Hellenistic art, and we owe it all to Alexander. In the wake of his conquests, Greek culture and language spread all over the ancient world, from Greece to India. Thanks to the common use of the Greek language, trade developed as merchants were always looking for business opportunities. Talking to buyers and sellers in the same language was a considerable asset. 

After the wars among Alexander’s successors were settled, peace returned in one form or another. Traffic and exchanges between East and West soon blossomed to reach a level never achieved before. 

Greek knowledge and culture were mixed and blended with the learning of Egypt, Mesopotamia, Central Asia, and India. In this context, Alexandria became the new center of the ancient world. 

It was in Alexandria that the first Library was created. In today’s words, this could be compared to a university. Ptolemy I Soter initially founded a Museum inside the Temple of the Muses (hence the name Museum), where all art and sciences were brought together. 

It seems that the Library was, in fact, an extension of the temple built by Ptolemy II Philadelphus, his son. Like every other building in Alexandria, we only have a slight idea of what it looked like, as, to this day, very few remains have been unearthed. An outstanding effort to visualize the great Library was made by Kevin Kok, Senior Level Artist at Ubisoft Montreal, to recreate the complex as it would or could have been (see: The Library of Alexandria). In time, the terms Museum and Library were used interchangeably. 

The Library of Alexandria certainly met Alexander’s own desire to create a research center where knowledge from East and West would be collected to be shared by all. The very concept existed already in the Academy and the Lyceum of Athens, but at Alexander’s death in 323 BC, the ancient world had grown into another dimension. We must credit Ptolemy for understanding Alexander’s vision and executing his ambition. 

Eventually, great scientists flocked to Alexandria, exchanging and discussing their understanding and perception of the world. Much research was done at the Museum, which held an astronomical observatory and rooms for anatomical dissections, and where all sorts of experiments were carried out. The site also included botanical and zoological gardens. How modern is that! 

It is generally accepted that Dimitrios of Phaleron was responsible for the organization. With the budget made available by Ptolemy II, he collected all the books he could, including the works of Aristotle and Theophrastus. Ptolemy III continued this trend, and the Library could boast of having half a million parchment rolls. Among them were all the great Greek works from Homer onward! 

After the death of Dimitrios, Zenodotus of Ephesus took over, assisted by Callimachus of Cyrene. This Callimachus is credited with being the first to classify 120,000 works of prose and poetry, sorting them by author and subject. Eratosthenes of Cyrene was appointed around 235 BC as the new head of the Library. He concentrated on mathematics, astronomy, and geography. We’ll remember Eratosthenes’ contribution to calculating the planet Earth's size after Pythagoras had declared that the Earth was a sphere (see: Alexander missed Eratosthenes by less than a century). 

Great scientists widely contributed to the Library. Euclid wrote his Elements of Geometry, which is still used today, and also a book on astronomy and one on perspective, the Optica. Archimedes, a native of Syracuse, probably studied in Alexandria. He is best known for his theory of calculating the volume, which he discovered while bathing. He was so excited about his discovery that he ran out of his house, stark naked, shouting, “Eureka!” - I found it! (see: Archimedes, the most illustrious citizen of Syracuse). The greatest astronomer of antiquity was Hipparchus of Nicaea, who made great use of the Library of Alexandria.  Besides being a geographer and a mathematician, he was also the inventor of trigonometry, and most famous for discovering the precession of the equinoxes in the late 2^nd century BC. 

Lesser known but equally important is Ctesibius of Alexandria, the inventor of toys and devices using air under pressure, i.e., pneumatics. He created automatons such as a water clock, a fire engine, and even a singing statue. He also invented the first keyboard-wind instrument, the hydraulis, a recreation of which is exhibited in the Museum of Dion, Greece (see: Close encounter with an ancient Water-Organ). 

By 62 AD, Hero of Alexandria even invented the first steam engine! Imagine our world if this invention had not been lost. 

The list of scientists, astronomers, mathematicians, physicians, and inventors seems endless. All their knowledge was born in Alexandria, from where it spread over the entire ancient world for more than three hundred years! The famous Lighthouse of Alexandria, the Pharos, was one of the Seven Wonders of the World, shining its light over a great distance thanks to an intricate system of mirrors. How it actually worked remains obscure. It was probably damaged by the catastrophic earthquake that hit the entire coast of North Africa in 365 AD. Repairs never resuscitated this unique structure. 

Alexandria was also the center where Medical Science was born under Herophilus. He was the first scientist to systematically perform dissections of dead people, often in public, to explain his actions to those interested in these matters. His books are lost but were frequently quoted in the 2nd century AD by the physician Claudius Galenus, better known as Galen of Pergamon (see: Hello? Dr. Galen?) 

Other Libraries were known from antiquity (see: Libraries in antiquity, a short overview), but none surpassed the one in Alexandria. 

After centuries of glory, this great Library succumbed to earthquakes and repeated fires. The lack of funds to sponsor and maintain the premises was another reason for its degradation. Eventually, the knowledge was transferred to Antioch, and with the Arab conquest to Baghdad. We owe very much to Caliph Al-Mansur (754-775 AD), who had a vivid interest in Greek science. He ordered the Greek documents to be translated into Arabic. Over the centuries, these translations traveled back west to become available in Latin. In fact, Al-Mansur saved ancient Greek literature and science for us to enjoy today. This entire process is developed in detail by John Freely in his book Aladdin’s Lamp. How Greek science came to Europe through the Islamic World.

Close encounter with an ancient Water Organ

Several years ago, I was browsing through the Archaeological Museum of Dion after exploring the nearby Macedonian sanctuary and Roman city. It is a lovely little museum but what truly impressed me was the water organ that stood on the first floor and was visited by only a handful of tourists. It was so recognizable as an organ that I even suspected that this reconstruction could be too far away from reality.

 

During excavations outside the beautiful Villa of Dionysus at Dion in 1992, archaeologists discovered a row of pipes together with large copper slabs bearing the imprints of pipes. After further examination in the on-site laboratory, they established that these pipes belonged to a water organ. It turns out to be the oldest surviving musical instrument of its kind, and it has been dated to the 1st century BC, making it 2,200 years old!

 

The ancient Greeks called it a ‘hydraulis,’ which first appeared in Alexandria. The first ‘hydraulis’ was built by Ctesibius and operated by compressed air channeled through a container of water to equalize the pressure. A row of pipes of different lengths produced the sound, and a polyphonic effect could be obtained by adding more pipes. What an invention! 

The arrival of the water organ was received with great success because of its powerful and pleasant sound, making it a favorite instrument in theaters, hippodromes, and other public gatherings. Eventually, it entered the Roman Imperial court. The Byzantines improved the organ and made it work without using water. The amazing fact is that this ‘hydraulis’ has been the ancestor of our church organs since the Middle Ages. 

Ancient music, more specifically Greek music, is an intriguing subject I tackled in earlier blogs (see: Reconstructing ancient music, an impossible task? and An insight into Ancient Greek Music). The history of this ‘hydraulis’ is another exciting contribution to this chapter.

 

The good news is that we will be able to listen to ancient Greek water-organ music at a live event - that is if you have the opportunity to travel to Athens this summer. The Acropolis Museum is organizing a free concert with quite an interesting program entitled "An introduction to the history of the ‘hydraulis’ and the discovery of the elements in Dion", given by Professor Pandermalis. 

[Reconstruction as shown in the Greek Reporter]

After that, the audience will be treated to a virtuoso recital on the ‘hydraulis” by the famous Greek organist, Ourania Gassiou. The concert will end with a special harp recital by harpist Thodoris Matoulas.