Archimedes' heat ray

Archimedes is purported to have invented a large scale solar furnace, sometimes described as a heat ray, and used it to burn attacking Roman ships during the Siege of Syracuse (c. 213–212 BC).

[4][5] In 2008, TV show Richard Hammond's Engineering Connections aired an episode, Deep Space Observer (S1E3), about the Keck Observatory, whose reflector glass is based on the Archimedes' Mirror.

In 2005, a group of students from MIT carried out an experiment with 127 one-foot (30 cm) square mirror tiles, focused on a mock-up wooden ship at a range of around 100 feet (30 m).

The MIT group repeated the experiment for MythBusters (s4e3 Archimedes Death Ray), using a wooden fishing boat in San Francisco as the target.

When MythBusters broadcast the result of the San Francisco experiment in 2006, the claim was placed in the category of "busted" (or failed) because of the length of time and the ideal weather conditions required for combustion to occur.

MythBusters also pointed out that conventional weaponry, such as flaming arrows or bolts from a catapult, would have been a far easier way of setting a ship on fire at short distances.