The tale is told that when the Romans were attacking Syracuse from the sea their boats were destroyed by an invention of Archimedes who was then working for the king of Syracuse. He built huge mirrors which were used to focus the rays of the sun onto the Roman boats, setting them on fire. Three questions come to mind. One, would this be possible, could Archimedes with the technology of the time, build such a mirror. Two, would it be practically possible to aim such a beam onto ships moving around the harbor? Three, if it were possible and you could set boats on fire, wouldn’t the same thing work on soldiers and sailors, and if so, wouldn’t this have a much more demoralizing effect on the Roman army? Any thoughts?
There was an attempt on one of these History channels to replicate this by using shields, I believe by a Greek professor in the 1960s. It did work. A ship may be anchored or moving slowly with no wind making it an easier target… Sinking a ship or setting it on fire ismore effiecient than attacking individual soldiers.
The BBC aren’t sure if it happened (bolding mine):
When the Romans invaded Syracuse in 214 BC, Archimedes invented ‘engines of war’ to defend the city, including cranes to drop rocks, claws to lift ships from the water, and machines to fire missiles. Most famous were the burning mirrors, with which Archimedes is supposed to have set ships on fire. This was theoretically straightforward: a parabolic mirror could be used to focus the rays of the sun onto one point, which would then reach temperatures sufficient to set alight anything at its focal point. The construction was more complicated, and Archimedes possibly approximated a parabolic mirror with a large number of small mirrors: the more mirrors, the closer the approximation.
Not being an engineer, I suppose that a mounted mirror would have some flexibility in following a target, depending where the sun is.
Boats are large wooden targets, and cost a lot of time and money. If one fire, the entire crew are now out of action.
Much better than trying for one fluid-filled person
The BBC aren’t sure if it happened (bolding mine):
When the Romans invaded Syracuse in 214 BC, Archimedes invented ‘engines of war’ to defend the city, including cranes to drop rocks, claws to lift ships from the water, and machines to fire missiles. Most famous were the burning mirrors, with which Archimedes is supposed to have set ships on fire. This was theoretically straightforward: a parabolic mirror could be used to focus the rays of the sun onto one point, which would then reach temperatures sufficient to set alight anything at its focal point. The construction was more complicated, and Archimedes possibly approximated a parabolic mirror with a large number of small mirrors: the more mirrors, the closer the approximation.
Not being an engineer, I suppose that a mounted mirror would have some flexibility in following a target, depending where the sun is at the time.
Boats are large wooden targets, and cost a lot of time and money. If on fire, the entire crew are now out of action.
Much better than trying for one fluid-filled person
God bless those MIT guys, they called it * Archimedes death ray*. The biggest problem, aside from clouds, mirrors, boats moving and the stray arrow would be tracking the sun.
Didn’t Mythbusters bust this one as well? Heck, if it was possible, nitwits would be doing it all the time for kicks.
D’oh, guess MIT > Mythbusters. Hehe.
The Mythbusters had an array of about a hundred mirrors. And they all had to be manipulated individually. The proved you could start a tiny smoldering patch on a stationary boat. If the boat held still. And the angle was juuuust right. And it would take an hour to set the 100 mirrrors just so, while the guys on the boat just sit and stare at you.
This would be a totally impractical weapon. One guy with a bow and some flaming arrows would be 100 times more effective.
Sure, it’d take an hour, if you only had one person setting them. So you get 100 folks, each with their own mirror to aim. Haven’t you ever played the game with reflecting a spot of sunlight off of your watch face around the walls of the room? Same thing, except there are 99 other guys playing at the same time.
As the Wiki link indicates, Mythbusters invited the MIT team to participate in their test.
So MIT = Mythbusters.
As I recall this story, Archimedes used ‘burning mirrors’ to set fire to the sails of ships.
That sounds much more feasible than setting the ship itself on fire. It’s possible the fire would spread to the ship from the sail. Certainly the sailors would be preoccupied for a while with fighting that fire. Even if they put it out, a ship without sails is reduced to rowing oars for motive power, and thus less effective.
Did Mythbusters test setting the sails on fire?
Yes. As I recall they were white which tended to reflect the heat and moved a bit to much in the breeze to get a good focus on a single spot.
Is it really unreasonable to think that Archimedes may have come up with some mechanism for connecting these hundred mirrors together in order to control them easily?
The other part of the story was the giant claws that reached out over the walls of Syracuse, picked up passing boats and smashed them into the water. There was a program on British TV a few years ago where some engineers tried to recreate it. I think they were able to lift the boat up out of the water, but not sink it.
I have fond memories of burning my school desk with a magnifying glass.
- a common pastime
The Greeks were quite technically competent, my understanding is that they regarded a lot of things as toys rather than labour saving devices.
As much as anything, having a tight beam of light flashed into your eyes would be pretty disconcerting - I would go for the steersman first, and then the sails.
I was really disappointed in the Mythbusters effort (and wrote them on their website ) You can do a lot better than they did. Their focal spot was patheically huge. After watching Jamie setting the mirrors, I’m, not surprised – they did it all mechanically, and I can (as an optics guy who’s had to adjust optics all the time) see plenty of ways it could go wrong. In the final analysis, you really do neede to adjust things optically, not mechanically. Even witb their system they should’ve gotten a better focus.
The Archimedes experiment has been verified numerous times, not only by MIT and the Greek guy. Buffon demonstrated it in the 18th century. Heck, France used to have (still has?) a “solar furnace” that could be used to melt metal at its focus.
One thing that did echo Archimedes’ device, as it was described, was to use fixed mirrors. But another early “solar weapon”, ascribed to Procls, used movable shields. This is what you really want, because such a device can “follow” the object and doesn’t have a fixed focal length. There are several methods you can use to guarantee that you are pointing your shield in the right direction to focus on the target. They’re the same methods that heliograph signallers use to make sure that their reflected sunlight gets to the person they’re trying to signal. They were described in an issue of the HJournal of the Optical Society of America back during WWII (when downed airmenm trying to be rescued needed to signal rescuers with their mirrors), and later used in the SF novel “Cycle of Fire” by Hal Clement. (Arthur C. Clarke also wrote a story where irate soccer fans used their glossy programs to incinerate a referree. I think it’s in “Tales from the White Hart”.)
It certainly was possible to use an offensive solar weapon in the time of Archimedes, but you’d need a trained and readu corps. I strongly suspect it never really happened, but it was technologically possible.
Here’s an article on the topic by someone I trust (page 2)
Since this is GQ FWIW:
The first full writing about the Siege of Syracuse is when Polybius wrote his Universal History ~ 200 B.C. He would almost certainly have had access to Romans who had been at the Battle. In his History, he doesn’t talk about the mirrors. Archimedes is like Batman – prepared with wonderful artillery anti-ship/personnel toys but he isn’t Captain Nemo – he doesn’t invent something that no one else has ever been able to replicate in ~2200 years of more or less constant scientific growth.
The same basic thing is true of two other ancient writers who touch it:
History of Rome from Its Foundation by Livy writing ~1 AD
Paralell Lives:MARCELLUS by Plutarch writing ~100 AD
Dio Cassius writing in about ~154 A.D. (IOW ~350 years later) first mentions the magic mirrors.
[Galen writing in the Second century mentions that Archimedes set the Roman ships afire but says he did it with burning catapulted pitch/oils]
Post summarized here
No, but it would be easier to have 1,000 (or 10,000) soldiers just individually aim their shields at the same spot.
<off-topic>
When you have slaves, you don’t have much economic incentive to invest in labor-saving devices.
That explains quite a bit of the nature of the Greek (and even more the later Roman Empire) economy, and their lack of any significant ‘technology’ development. Despite having a centralized government, an educational system, and long periods of peace.
</off-topic>
It is very unlikely that a warship of that era would have had the sails up that close to combat. Ships under sail are too difficult to maneuver. A stray flaming arrow would ruin your day, never mind 20’s style death rays.