Most people with an interest in the history of science have heard the famous story of “Archimedes’s death ray.” In case you are unfamiliar with it, it goes like this: Supposedly, during the Siege of the Greek city of Syracuse by the Romans, lasting from spring of 213 BC through autumn of 212 BC, the brilliant Syracusan inventor and mathematician Archimedes (lived c. 287 – c. 212 BC) developed a spectacular invention to keep the Roman ships at bay; he built a death ray using mirrors to concentrate the light of the sun on the Roman ships, thereby setting them on fire. Unfortunately for all the people out there who love a good story about a brilliant inventor fending off enemy forces using science, the story of “Archimedes’s death ray” is certainly apocryphal.
Totally absent from all our earliest sources
Archimedes of Syracuse was undoubtedly a real person and the Siege of Syracuse by the Romans from spring of 213 BC through autumn of 212 BC was undoubtedly a real historical event. These details of the story are beyond all serious dispute. Likewise, it is probably historically true that Archimedes really did use many clever inventions to help defend his city against the Romans. Indeed, it may very well have been due in part to his innovations that the city was able to hold out so long.
Unfortunately, however, for fans of the death ray story, none of the sources written anywhere near the time when Archimedes was actually alive mention anything at all about the supposed solar death ray. If Archimedes really built a death ray using mirrors, then we would expect the story to be reported in all the earliest sources talking about Archimedes’s defense of Syracuse. This is not so, however.
The Greek historian Polybios of Megalopolis (lived c. 200 – c. 118 BC), the Roman historian Titus Livius (lived 64 or 59 BC – AD 12 or 17), and the Greek biographer Ploutarchos of Chaironeia (lived c. 46 – c. 120 AD) all give detailed accounts of the Roman siege of Syracuse and not one of them ever mentions anything about Archimedes having built a death ray to defend the city.
ABOVE: The Greek historian Polybios of Megalopolis, shown here in a carving from the Stele of Kleitor, writing just one generation after Archimedes, gives a detailed account of the Siege of Syracuse, but never mentions the supposed “death ray.”
Furthermore, Archimedes’s younger contemporary, the mathematician Diokles (lived c. 240 – c. 180 BC), wrote a surviving treatise on the uses of burning mirrors, but, for some reason, Diokles never mentions anything about Archimedes’s so-called “death ray.” Again, this would be an extraordinary omission if the story of Archimedes’s death ray were indeed true, especially considering that Diokles mentions Archimedes in the treatise in connection with a geometric problem, proving beyond all doubt that Diokles was aware of Archimedes and his work.
Two extremely vague allusions from four centuries later
There are two sources from the late second century AD—about four hundred years or so after Archimedes’s death—that make very brief, offhand mention Archimedes having set fire to the Roman ships. Both of these references, however, are extremely vague as to how he is supposed to have done this and neither of them mentions anything at all about mirrors, the sun, reflective surfaces, or burning lenses in relation to the story.
One of these two mentions comes from the essay Hippias, or the Bath, which is traditionally attributed to the Syrian satirist Loukianos of Samosata (lived c. 125 – after c. 180 AD) but is now generally agreed to have not actually been written by him. Loukianos lived roughly 400 years after Archimedes’s death. The anonymous author of Hippias, or the Bath must have been writing around that time or possibly even later.
Hippias, or the Bath, however, mentions nothing at all about a death ray made of mirrors; instead it only says that Archimedes “…burned the ships of the enemy using science.” (In Greek, it says “τὸν δὲ τὰς τῶν πολεμίων τριήρεις καταφλέξαντα τῇ τέχνῃ.” The word τέχνη means “skill,” “science,” or “art.” In this context, it probably means “science.”)
The other of these two mentions comes from the medical treatise On Temperament by the Greek doctor Galenos of Pergamon (lived c. 129 AD – c. 200/c. 216 AD), who mentions in an offhand remark, “in some such manner, I suppose that Archimedes is said to have set fire to the enemy ships using fiery stuff.” (In Greek, he says, “οὕτω δέ πως, οἶμαι, καὶ τὸν Ἀρχιμήδην φασὶ διὰ τῶν πυρείων ἐμπρῆσαι τὰς τῶν πολεμίων τριήρεις.” The exact meaning of the word πυρεία is obscure, but it clearly has something to do with fire, hence why I have translated it as “fiery stuff.”)
ABOVE: Fictional eighteenth-century portrait of the Greek doctor Galenos of Pergamon by Georg Paul Busch. (No one knows what the historical Galenos really looked like.)
Great. The most detailed description we get out of these two is that Archimedes used “science” and “fiery stuff” to set fire to the enemy ships. For all we know, this could be intended to mean that Archimedes built a giant catapult and launched flaming hay bails at the Roman ships, since, after all, catapults are “science” and flaming hay bails are, after all, “fiery stuff.”
Likewise, these authors could with equally as much plausibility be interpreted as trying to claim that Archimedes invented Greek fire around a millennium in advance and mounted pumps to the fronts of the Syracusan ships and used them to spray the incendiary liquid at the enemies. I would say Greek fire would definitely count as both “science” and “fiery stuff.”
Oh, here is another equally plausible explanation: These writers could be claiming that Archimedes hired an exceptionally talented fire-breather to sneak on board the Roman ships and breath the fire he had been hiding in his mouth all over the place, setting fire to the ships! A crazy stunt like that certainly would undoubtedly count as “skill” (another possible meaning of the word τέχνη, if you recall) and I would say fire-breathing definitely counts as “fiery stuff.”
Now, of course, I am sure you can all tell that I am being deliberately ridiculous to prove the point that these accounts are extremely vague. I am not seriously proposing any of these possibilities I have suggested here. All of these options I have presented are intentionally absurd. Quite simply, neither Hippias, or the Bath nor Galenos say anything useful at all about how Archimedes burned the Roman ships; they just claim that he did.
Then, of course, there is the other problem that the anonymous author of Hippias, or the Bath and Galenos both lived around four centuries after Archimedes and this whole story about Archimedes setting fire to the Roman ships is not reported by any earlier sources, even though there are plenty of earlier sources covering the Siege of Syracuse.
This would like if a source written this year in 2019 made a claim about something that happened in the 1600s that was not mentioned by any earlier known sources. Quite simply, this fact in itself gives us pretty good reason to think that the whole story is probably completely apocryphal anyways.
ABOVE: Twelfth-century AD manuscript illustration from the Madrid Skylitzes showing the Byzantines using Greek fire against a rebel ship
Baseless speculation from seven centuries later
The first source to mention Archimedes using mirrors to set fire to the enemy ships is On Burning Glasses by the Greek architect and mathematician Anthemios of Tralles (lived c. 474 – 533 x 558 AD), who lived roughly 700 years after Archimedes. But wait! It gets better, because Anthemios only states that Archimedes “might have” used mirrors to set fire to the Roman ships. In other words, he was aware of the tradition from Hippias, or the Bath and Galen that Archimedes had burnt the Roman ships “using science” and was only speculating that Archimedes might have done this using mirrors.
In other words, the whole famous story about Archimedes burning the Roman ships using mirrors is just a tidbit of speculation by a writer who lived 700 years after Archimedes based on a legend that originated around 400 years after Archimedes. Later writers who had read Anthemios’s work repeated his speculations about the mirrors and added more details to the story, causing the story to develop into the story we know today.
Ironically, there are actually currently multiple versions of the story in popular circulation. For instance, sometimes it is said that Archimedes actually built a contraption made out of mirrors to focus the sun’s rays. Other times, however, it is instead claimed that Archimedes merely told all the Syracusan soldiers to stand along the shore holding their reflective bronze shields in a certain formation at a certain time of day. The story has become a piece of modern folklore, but, despite its continued popularity, it is still as apocryphal as any story can be.
ABOVE: Incidentally, Anthemios of Tralles was also one of the two architects who designed the great Hagia Sophia cathedral in Constantinople. Shown above is the interior dome of the Hagia Sophia.
Could it have worked, though?
Even though it is abundantly clear by this point that Archimedes definitely did not really try to build a solar death ray using mirrors, this still does not answer all our questions. Most of you are probably wondering at this point, “Could the death ray have worked, if Archimedes had tried to build it?” Sadly, as awesome as I am sure most people think it would be to defend a city against the Romans using a solar death ray, the answer to this question is that it is highly unlikely that a solar death ray using mirrors could ever have been used as a practical weapon of defense during an actual siege.
A group of students from the Massachusetts Institute of Technology tested one version of the death ray myth in October 2005. They did manage to ignite a portion of the ship, but only after ten full minutes of unobstructed sunlight with the ship remaining stationary in the harbor. In other words, they did manage to get the death ray to work, but the conditions under which they got it to work were far from realistic siege conditions. In a real siege, the sky might not be clear, the ships would be moving, and you might not have time to wait there for ten whole minutes.
The Discovery channel television series Mythbusters tested the death ray myth no less than three times. Each time they tested it a different way and, each time, they concluded that the death ray was not a practical or efficient weapon, designating the myth “Busted” all three times.
The results of these experiments are not especially surprising. If you really think about it, the whole solar death ray idea, while it may be possible in theory, seems like it would be ludicrously near-impossible to actually try to implement during an actual invasion. Just imagine all the factors that would have to work just right in order for the death ray to even be plausible.
First of all, it would have to be a perfectly clear day with lots of sunlight. Also, since Syracuse faces the sea towards the east, it would have to be early morning. The sun, the mirrors, and the ships would all have to be in exactly the right positions. The mirrors would need to be at exactly the right angles. The ships would need to stay in one place long enough for them to catch fire. There are so many points at which the whole scenario could easily go wrong. This is the sort of idea that requires so much precision that it just would not be practical under actual siege conditions.
ABOVE: The Death of Archimedes, painted in 1815 by the French Neoclassical painter Thomas Degeorge
