Philo of Byzantium, also called Philo Mechanicus or "Philo the Engineer" in Latin, was a Greek engineer, physicist, and writer about mechanics. He lived during the second half of the 3rd century BC, from around 280 BC to around 220 BC. Although he was born in Byzantium, he spent most of his life in Alexandria, Egypt. Some sources say he was born about 100 years before Ctesibius, but others think he was younger.
Works
Philo wrote a large book called the Syntaxis (Ancient Greek: Mēkhanikḗ Sýntaxē, meaning "System of Mechanics"). This work included several sections:
- Isagoge ("Introduction") – general mathematics
- Mochlica ("Concerning Leverage") – mechanics
- Limenopoeica ("Harbour Construction")
- Belopoeica ("Siege Engine Construction")
- Pneumatica ("Pneumatics")
- Automatopoeica ("Construction of Automatons") – mechanical toys and diversions
- Parasceuastica ("Preparations") – for sieges
- Poliorcetica ("Siegecraft")
- Peri Epistolon ("On Correspondence") – coding and hidden letters for military use
Parts of Belopoeica and Poliorcetica still exist in Greek. They describe missiles, fortress building, and strategies for attack and defense. Fragments of Isagoge and Automatopoeica also survive (edited by R. Schone, 1893; translated by Hermann August Theodor Köchly, 1853; and by E. A. Rochas d'Aiglun, 1872).
Another section about pneumatic engines is preserved in a Latin translation (De Ingeniis Spiritualibus) of an Arabic version (edited by W. Schmidt, 1899; translated by Rochas, 1882). Other parts may appear in the works of Vitruvius and Arabic writers.
The Philo line, a geometric method to double the cube, is named after Philo.
Recent research suggests that a section of Philo’s Pneumatics once thought to be a later addition contains the first recorded description of a water mill, invented by Greeks around the mid-third century BC.
Philo’s work also includes the earliest known use of a chain drive in a repeating crossbow. Two flat chains connected to a windlass would automatically fire arrows until the magazine was empty.
Philo described a gimbal: an eight-sided ink pot that could be turned in any direction without spilling. The inkwell was suspended at the center, attached to metal rings that stayed still no matter how the pot was rotated.
In Pneumatics (chapter 31), Philo explained an escapement mechanism, the earliest known, used in a washstand. A counterweighted spoon filled with water from a tank would tip into a basin, releasing pumice. When the spoon emptied, the counterweight pulled it back, closing the pumice door with a string. Philo noted that this mechanism was similar to those in ancient water clocks.
Philo is also credited with creating the first thermoscope, an early version of a thermometer.
In mathematics, Philo solved the problem of doubling the cube. This involved constructing a second catapult that could fire a projectile twice as heavy as the first. His solution used the intersection of a rectangular hyperbola and a circle, a method similar to one later used by Hero of Alexandria.
A treatise titled Seven Wonders of the World (Ancient Greek: Perì tō̂n Heptà Theamátōn) is sometimes linked to Philo. However, it likely belongs to a different Philo, a later writer from Byzantium, who lived in the 4th–5th century AD. This work was printed by R. Hercher in an edition of Aelian (Paris: Firmin Didot, 1858). An English translation by Jean Blackwood is included in The Seven Wonders of the World by Michael Ashley (Glasgow: Fontana Paperbacks, 1980).