Philo of Byzantium

Philo of Byzantium (Φίλων ὁ Βυζάντιος, Philōn ho Byzantios, ca. 280 BC – ca. 220 BC), also known as Philo Mechanicus, was a Greek engineer and writer on mechanics, who lived during the latter half of the 3rd century BC. Although he was from Byzantium he lived most of his life in Alexandria, Egypt. He was probably younger than Ctesibius, though some place him a century earlier.

Life and works
Philo was the author of a large work, Mechanike syntaxis (Compendium of Mechanics), which contained the following sections:
 * Isagoge (εἰσαγωγή) - an introduction to mathematics
 * Mochlica (μοχλικά) - on general mechanics
 * Limenopoeica (λιμενοποιικά) - on harbour building
 * Belopoeica (βελοποιικά) - on artillery
 * Pneumatica (πνευματικά) - on devices operated by air or water pressure
 * Automatopoeica (αὐτοματοποιητικά) - on mechanical toys and diversions
 * Parasceuastica (παρασκευαστικά) - preparation for sieges
 * Poliorcetica (πολιορκητικά) - on siegecraft
 * Peri Epistolon (περὶ ἐπιστολῶν) - on secret letters

The military sections Belopoeica and Poliorcetica are extant in Greek, detailing missiles, the construction of fortresses, provisioning, attack and defence, as are fragments of Isagoge and Automatopoeica (ed. R. Schone, 1893, with German translation in Hermann August Theodor Köchly's Griechische Kriegsschriftsteller, vol. i. 1853; E. A. Rochas d'Aiglun, Poliorcetique des Grecs, 1872).

Another portion of the work, on pneumatic engines, has been preserved in the form of a Latin translation (De ingeniis spiritualibus) made from an Arabic version (ed. W. Schmidt, with German translation, in the works of Heron of Alexandria, vol. i., in the Teubner series, 1899; with French translation by Rochas, La Science des philosophes... dans l'antiquité, 1882). Further portions probably survive in a derivative form, incorporated into the works of Vitruvius and of Arabic authors.

The Philo line, a geometric construction that can be used to double the cube, is attributed to Philo.

A treatise conventionally titled De septem mundi miraculis, on the Seven Wonders of the World, is properly ascribed to another Philo of Byzantium, known as "the Paradoxographer", who belongs to a much later date, probably the 4th-5th century A.D. It is printed in R. Hercher's edition of Aelian (Paris: Firmin Didot, 1858); an English translation by Jean Blackwood is included as an appendix in The Seven Wonders of the World by Michael Ashley (Glasgow: Fontana Paperbacks, 1980).

Devices


According to recent research, a section of Philo's Pneumatics which so far has been regarded as a later Arabic interpolation, includes the first description of a water mill in history, placing the invention of the water mill in the mid-third century B.C. by the Greeks.

Philon's works also contain the oldest known application of a chain drive in a repeating crossbow. Two flat-linked chains were connected to a windlass, which by winding back and forth would automatically fire the machine's arrows until its magazine was empty.

Philon also was the first to describe a gimbal: an eight-sided ink pot with an opening on each side could be turnt so that any face is on top, dip in a pen and ink it-yet the ink never runs out through the holes of the side. This was done by the suspension of the inkwell at the center, which was mounted on a series of concentric metal rings which remained stationary no matter which way the pot turns itself.

In his Pneumatics (chapter 31) Philon describes an escapement mechanism, the earliest known, as part of a washstand. A counterweighted spoon, supplied by a water tank, tips over in a basin when full releasing a pumice in the process. Once the spoon has emptied, it is pulled up again by the counterweight, closing the door on the pumice by the tightening string. Remarkably, Philon's comment that "its construction is similar to that of clocks" indicates that such escapements mechanism were already integrated in ancient water clocks.

Mathematics
In mathematics, Philo tackled the problem of doubling the cube. The doubling of the cube was necessitated by the following problem: given a catapult, construct a second catapult that is capable of firing a projectile twice as heavy as the projectile of the first catapult. His solution was to find the point of intersection of a rectangular hyperbola and a circle, a solution that is similar to Heron's solution several centuries later.