Sunday, November 1, 2015

Archimedes and the Burning Mirror


Archimedes – Turned His Skills on Invaders, Holding them at Bay

It was during the Second Punic War when the city of Syracuse in Sicily had made the serious mistake of supporting the Carthaginians against Rome and in 216 BC the huge Roman fleet set out to lay siege to Syracuse and capture it. It would have been a simple task for the well-drilled Romans though they had not figured out on the intervention of a 70 year old man, Archimedes, who was the greatest Greek technologist, a born and bred Syracusian.

Though he detested violence, having no interest absolutely in military campaigns, in the hour of need in his home town, he turned his skill on the invaders, helping in holding them at bay for almost four years. The Roman had not seen some of the war machines that were released on them.

A large pair of forceps had appeared from the city walls and had grasped the hull of the ship between its jaws, shook it and had sent it crashing in ruins in the sea. Giant catapults had hurled showers of heavy spears and stones on the vessels at anchor a few distances from the shore. However, there was one weapon which Archimedes is said to have used that defied integrity.

Comprehended Reflection

One of the writers worth mentioning was Plutarch who had an interest in making Greek brains far superior to the Romans. As per Plutarch, Archimedes redirected the Sun’s rays on to the Roman galleys setting them ablaze. This incident is not known whether it is true or not, but seemed too good for the medieval chroniclers over thousands of years later to resist.

Some of the later writers state that Archimedes used the published round shields of the Greek troops to reflect the sunlight while others claim that he had focused the rays with a giant single mirror, A Byzantine historian of the 12th century, Joannes Zonaras wrote that, at last in an incredible manner, he burned up the whole Roman fleet by tilting a kind of mirror, he ignited the air from the beam and kindled a great flame, he directed at the ships at anchors in the path of the fire till he consumed them all. Zonaras, obviously had only a weak grasp on the principles of optics but Archimedes on the other hand comprehended reflection as well as anyone till the time of Newton and even he would have struggled to exploit it as an combustible weapon.

Mirrors Used As Anti-Personnel Weapons

Possibly, mirrors might have been used as anti-personnel weapons. For instance, fifty mirrors, precisely trained on the steersman of a Roman galley could have given him a horrible burn but the scene of the total fleet being disabled in this way seems to be a bit unconvincing.

The ability of mirrors to concentrate the sun in obtaining high temperature is well-known. It is easy to envisage focusing the mirrors on a wooden ship rather than the tower to set it ablaze. The goal at the top of the tower could reach temperatures more than 1,000 Fahrenheit, about the auto-ignition point of most wood. But each of the installed mirrors were massive and could have been around 2000 of them, probably which Archimedes may have not arranged considering the technology during that time.

Probably the account of Archimedes together with his military mirrors could be the result of distraught imagination. The actual destruction of the Roman ships as claimed by Thucydides and Aeneas Tacitus was that they could have been due to burning gobbets of sulphur, pitch and charcoal tossed from shore-based catapults and this could have inspired the legend.

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