High walls protected the city of Syracuse, equipped with catapults and crossbows strategically placed at key points of the fortification. The Romans besieged the city for months, by land and sea, with discreet results. The genius of the mathematician Archimedes was on the side of the Greek polis.
It was the year 214 BC, in the middle of the Second Punic War (218-201 BC) between the Roman Republic and Carthage. Syracuse, located on the eastern coast of Sicily, had been close to Rome for decades, but times were changing and a new faction rose to power on the island, threatening to ally itself with Hannibal Barca.
The troops commanded by General Marcus Claudius Marcellus surrounded the city, hoping for its quick surrender. But they did not count on the fact that the tyrant Epicides had convinced Archimedes to help in the defense. The Greek mathematician, one of the most important scientists of Antiquity, put all his ingenuity at the service of the polis.
Among the war inventions attributed to him is a crane with a claw that supposedly lifted ships out of the water before dropping them from a great height (which would have prevented the Romans from storming the city). Although the most notable would have been the ‘death ray’, a weapon that was to take advantage of the heat of the sun to set enemy ships on fire.
According to the Greek historian Lucian, Archimedes placed mirrors along the bay of Syracuse to focus the sun’s rays on enemy ships, causing them to burst into flames. For centuries, scientists have doubted that this device actually existed and that it even worked. Until a Canadian boy of just 12 years old has demonstrated the viability of the instrument.
Brender Sener, a high school student from Ontario, has been able to certify that the “death ray” (or heat ray) can work after building a small-scale mock-up, a tabletop version of the weapon, using concave mirrors and LED desk lamps.
During his experiments, the boy discovered that by using the reflectors to focus a 50-watt heat source on a piece of cardboard, the temperature of the target could increase by 2° Celsius with each additional mirror, until a total of three reflectors were added.
The big change, however, came when he added a fourth mirror that caused a huge temperature jump of up to eight degrees. When he repeated the process using a 100-watt lamp, he found that “the temperature change with each mirror was 4°C up to three mirrors and an additional 10°C with the fourth,” he explains in an article published in the journal The Canadian Science. Fair Journal, a publication specializing in children’s and youth science projects from across Canada.
“Based on my experimental findings, I believe that with a strong enough heat source and multiple larger mirrors, all focused at a perfect angle, combustion could be possible,” writes the study’s author. “Historical descriptions of the use of the death ray in ancient Syracuse are plausible, although no archaeological evidence has been found beyond what is recorded in the books of ancient philosophers,” he adds.
Some renowned researchers, such as the French philosopher René Descartes, tried for centuries to dispel doubts about Archimedes’ inventions, although the vast majority came to the conclusion that this weaponry was the result of fiction. At least, until 1973, when Greek scientist Ioannis Sakkas argued that the contraption was possible.
Sakkas lined up nearly 60 sailors holding mirrors and had them redirect sunlight toward a focal point on a wooden boat 50 meters away. The ship, which was smeared with bitumen, reportedly caught fire within a short time. In 2004, scientists at MIT used 127 mirrors to successfully light a model of a Roman trireme.
A few months later, however, MIT engineers collaborated with the Mythbusters program to repeat the test. They installed 300 bronze searchlights along San Francisco Harbor and pointed them at a replica of a Roman warship about 200 feet away. The wooden hull smoked and smoldered, but there were no flames.
They tried again from 30 meters away and managed to start a small fire, which was quickly extinguished. So they concluded that the heat ray of Archimedes (who died at the end of the siege of Syracuse, in 212 BC, at the hands of a Roman soldier) was possible but impractical with moving ships.
