科技史宇宙Civiliverse

Person

Archimedes

阿基米德 Ἀρχιμήδης

He turned the lever and buoyancy into geometrical proofs, and weighing into a way of discovering geometry.

View in the atlas

Mathematician and engineer of Syracuse (c. 287–212 BCE). He proved the law of the lever and the principle of buoyancy, trapped π between 3 10/71 and 3 1/7, and was killed when Rome took the city.

Date
c. 287–212 BCE
Place
Syracuse, Sicily
Civilisation
Greco-Roman
Fields
Mathematics & Computing, Natural Philosophy & Method

Give me a place to stand on, and I can move the earth.

—— Attributed to Archimedes by Pappus of Alexandria, Collection VIII.11 (early 4th century CE; ed. Hultsch, p. 1060), trans. T. L. Heath
A page of the Archimedes Palimpsest. The tenth-century copy of On Floating Bodies and other works was scraped and overwritten as a prayer book in the thirteenth century.
A page of the Archimedes Palimpsest. The tenth-century copy of On Floating Bodies and other works was scraped and overwritten as a prayer book in the thirteenth century.public domain, via Wikimedia Commons source

History

The law of the lever states that two weights balance at distances from the fulcrum inversely proportional to their weights. In On the Equilibrium of Planes Archimedes proved it from a few postulates, the earliest surviving axiomatic statics. Born in Syracuse around 287 BCE, the son of the astronomer Phidias, he spent most of his life there, close to King Hieron II. On Floating Bodies showed that a body immersed in a fluid loses weight equal to the weight of the fluid it displaces; Measurement of a Circle used 96-sided polygons to trap π between 3 10/71 and 3 1/7; Quadrature of the Parabola found a parabolic segment to be 4/3 of its inscribed triangle; The Sand Reckoner devised a notation for numbers large enough to count the grains filling the cosmos, and preserved Aristarchus' hypothesis of a moving Earth. When Rome besieged Syracuse from 214 BCE, Polybius, Livy and Plutarch describe his catapults and an iron "claw" that hoisted ships by the prow; the city fell in 212 BCE and a Roman soldier killed him. Cicero adds that the Roman commander Marcellus carried home a sphere he had made to show the motions of sun, moon and planets. In 75 BCE Cicero, then quaestor in Sicily, found his neglected tomb, marked with a sphere inscribed in a cylinder. The "Eureka" bath comes from Vitruvius nearly two centuries later; the burning mirrors are later still.

Why it matters

Archimedes matters because traffic between machine and proof ran both ways in his work. Lever and buoyancy, long known to craftsmen, became theorems. Conversely, The Method, addressed to Eratosthenes, explains how he first found areas and volumes by "weighing" thin slices of figures on an imaginary balance and then proved the results by exhaustion, keeping investigation and demonstration strictly apart. The treatise survived in a single tenth-century copy, overwritten as a prayer book in the thirteenth century; Heiberg recognized it in 1906, and multispectral imaging in 1999–2008 recovered much more. Plutarch's sage who scorned every art serving the needs of life says more about Plutarch's Platonism than about the author of The Method. The famous boast, as Pappus reports it, mentions neither lever nor fulcrum; it concerns moving a given weight with a given force. Galileo took him as a model in La Bilancetta (1586), and the habit of settling physical questions by mathematical proof runs back to him.

Connections

Causes1

Consequences1

Echoes2

Sources

Open questionswell attested