Sunday, October 23, 2005

The Archimedes Mirror Battle Tactics Reproduced (sort of)


By Elaine Meinel Supkis

The University of Arizona (my school, yaboo!) and MIT decided to try reproducing the famous Achimedes mirrors burning ships battle tactics. Seemingly, it failed. I will explain why.

From Yahoo:
It wasn't exactly the ancient siege of Syracuse, but rather a curious quest for scientific validation. According to sparse historical writings, the Greek mathematician Archimedes torched a fleet of invading Roman ships by reflecting the sun's powerful rays with a mirrored device made of glass or bronze.

More than 2,000 years later, researchers from the Massachusetts Institute of Technology and the University of Arizona set out to recreate Archimedes' fabled death ray Saturday in an experiment sponsored by the Discovery Channel program "MythBusters." Their attempts to set fire to an 80-year-old fishing boat using their own versions of the device, however, failed to either prove or dispel the myth of the solar death ray.

The MIT team's first attempt with their contraption made of 300 square feet of bronze and glass failed to ignite a fire from 150 feet away. It produced smoldering on the boat's wooden surface but no open flame. A second attempt from about 75 feet away lit only a small fire that burned itself out.
An 80 year old fishing boat isn't what these ancient ships were. For one thing, I know old boats well. If they have been sitting idle for many years, they are wet with rain water collecting within the wood, ie, rotten. Ever try to start a rotten fire? I have.

It is very hard. The punkier the wood, the harder it is to set it on fire, outdoors. If it is stored indoors, it will be dryrot which burns easily but I assume this old boat was lying outside, untended, and thus, wet inside. All boats left ashore and untended tend to get wet rot.

Further, how did the Romans or everyone keep their boats water-proof? The ancient mariners who ceased using hide boats or wooden canoes had to deal with sealing the planks used to build ships. For this, nearly everywhere, they used pine pitch in the north or in the Middle East...oil. So, from my experience with dealing with old peices of wood from piers and ships, they are oil soaked if they are more than 100 years old. The older, the more oil soaked. Up until vanishes were used instead which is about 1900.

So...the boat used in this experiment probably was a varnish covered boat that lost its varnish, not an oil soaked boat that was very much afloat and probably "primed" just be for launching to go to war.

Further, what if the part set afire was the sail? They used sheep's wool sails and this is more burnable than wood and further, probably, since it was laid down on the decks of the oily boats, wool soaks up oil, too. Thus, it ignites.
In "Epitome ton Istorion," John Zonaras wrote: "At last in an incredible manner he 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
Since the ships were at anchor, and since the mirror array was overhead, the beams would have not been concentrated on the hulls but rather on the decks where the sails laid like some candle wicks, perhaps.

My family has a fondness for this story because of my parent's work on solar arrays and multimirror telescopes. Both of my parents collect pictures about this event. We talk about it. It astonishes me that the students doing this trick didn't consult with authorities about Roman ships, first.

And next: the story about the turtle dropping on poor Archimedes' head. Any mathematicians willing to try out that story?

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