Archimedes Mirror

Ancient high-tech development of solar technology: wall painting from the Uffizi Gallery, Stanzino delle Matematiche, in Florence, Italy, showing the Greek mathematician Archimedes’ mirror being used to burn Roman military ships. Painted in 1600 by Giulio Parigi. © 2009, Dennis R. Holloway Architect

EPITOME TON ISTORION

by John Zonaras (circa twelfth century AD)

9, 4At last in an incredible manner he [Archimedes] burned up the whole Roman fleet. For by tilting a kind of mirror toward the sun he concentrated the sun’s beam upon it; and owing to the thickness and smoothness of the mirror he ignited the air from this beam and kindled a great flame, the whole of which he directed upon the ships that lay at anchor in the path of the fire, until he consumed them all.

The above passage is from

DIO’S ROMAN HISTORY
Translated by Earnest Cary
Loeb Classical Library
Harvard University Press, Cambridge, 1914
Volume II, Page 171

BOOK OF HISTORIES (CHILIADES)

by John Tzetzes (circa twelfth century AD)

Book II, Lines 118-128

When Marcellus withdrew them [his ships] a bow-shot, the old man [Archimedes] constructed a kind of hexagonal mirror, and at an interval proportionate to the size of the mirror he set similar small mirrors with four edges, moved by links and by a form of hinge, and made it the centre of the sun’s beams–its noon-tide beam, whether in summer or in mid-winter. Afterwards, when the beams were reflected in the mirror, a fearful kindling of fire was raised in the ships, and at the distance of a bow-shot he turned them into ashes. In this way did the old man prevail over Marcellus with his weapons.

The above passage is from

GREEK MATHEMATICAL WORKS
Translated by Ivor Thomas
Loeb Classical Library
Harvard University Press, Cambridge, 1941
Volume II, Page 19

The Burning mirrors are mentioned by Lucian of Samosata and Galen. Anthemius of Tralles (474-534), the Architect of the Hagia Sophia, tells us that Archimedes used many mirrors. Johannes Zonaras in 1118 says that first Archimedes used the “iron Hand” against the ships and then he burned these with mirrors.

Proclus used a similar method in 514 against the ships of Vitellius. Fire was emitted from the mirrors that looked like a flash. Johannes Tzetzes says that hexagonal mirrors were used. Zonaras and Tzetzes used sources from Cassius Dio and Diodorus Siculus. Girolamo Cardano discussed the possibility of using spherical mirrors for ships in 1.5 km distance. Cardano proposed a mirror with only 1/60 of the total spherical perimeter that still is around 300 m!

the flash-point of wood which as all readers of Science Fiction know is “Fahrenheit 451”