Sunday, 4 November 2012

Roman era cannons?

You've probably heard of Archimedes 'super weapons' - there's the ever present 'Solar Heat Ray' that 'Mythbusters' keep trying to perfect, the troublesome 'Claw' or 'ship-shaker', which did exist but no one has a clue how it worked, and then there's the 'steam cannon'. All of these were supposedly used by the Sicilians against Roman invaders in 212BC, but with the death of the inventor during this campaign - and no doubt many of those who'd built and operated these machines - their use or effectiveness was largely forgotten. Even the Romans who had been confronted by these 'super weapons' appear to have been quick to eschew them - perhaps more concerned with the designs falling into Carthaginian hands than any advantages they might bring to Classical era warfare. But the question is, what if some of these weapon designs were perpetuated? Is it possible?

Well, it's by no means conclusive proof, but during the siege of Massilia (April 19th-September 6th 49BC) Julius Caesar makes mention of a weapon that may have come from Archimedes arsenal. First of all, who were the Massilians? In 49BC, Massilia - now modern day Marseilles - was the largest independent Greek city state left in the world. Around 400,000 Ionian Greeks and Gauls lived within the walls of the largest city west of Rome and despite nearly one hundred years of conquests in both Gaul and Greece, various Roman generals, including Julius Caesar had left this place well alone. Massilia wasn't necessarily a military city, it was an economic hub - a Gallic Hong Kong - through which much of Gaul's export and imports had been funnelled for some 400-years. But this had made the city rich, which meant it could afford the best in defensive weapons from its fellow Greeks - weapons that remained untested on Roman armies until Julius Caesar crossed the Rubicon. As the civil war expanded, Massilia sided with the Pompeians, which made it a serious thorn in Caesar's supply lines between Northern Italy and Spain.

Now, to overtop Massilia's massive walls, Caesar reports his Senior Legate - Gaius Trebonius - had to build 80-foot high seige walls, and it was during this construction the Caeasarian legions were attacked with 'ballistae' firing twelve-foot long timber poles tipped with spikes - these enormous darts were capable of piercing four layers of wicker work the Romans were working behind. Okay, a standard ballistae could have fired such a dart, although traditionally they didn't. However, one aspect of Archimedes steam cannon involves the cannon not only firing the cannon ball, but also a long length of timber. Why a long length of timber? Well, a steam cannon is pretty simple, a bronze or copper barrel - much like any muzzle loading gunpowder cannon - has its solid end placed over a fire. A spherical stone or metal projectile is loaded down the muzzle, a piece of timber the length of the barrel - minus the size of the ball - is then fitted down the barrel, holding the ball in place and in turn being held in place by a timber slat that stretches across the muzzle. Now the cannon is loaded. To fire, a valve is opened that feeds water into the red hot barrel end still sitting over the fire. The water turns to steam and at a set pressure, the timber slat breaks - releasing the timber pole and the ball. Being lighter, the timber pole might actually travel further than the ball - and there's no reason it couldn't be weaponised with an iron spike. Was this what Trebonius' troops came up against? Well, I think it is safe to say it can't be fully ruled out. With no moving parts, immense power and restricted only by an army's supply of fuel and projectiles, the steam cannon could have been the reason why the Massilians stayed independent as long as they did.