The efficacy of Archimedes’ lenses for burning purposes has been argued for centuries. This much is certain: they did not succeed in their purpose for Marcellus sacked the city in 212 B.C., after the walls had been stormed. Archimedes was killed but after his death he was honored even by the invader Marcellus, who ordered a monument erected over his grave. One explanation is that the Burning Glasses of Archimedes were used in what would now be called psychological warfare. Archimedes knew how to construct glasses, systems that would set small fires at a close range; the enemy knew this. So what better ruse would there be than to construct a gigantic Burning Glass atop the highest building of Syracuse, clearly in view of the enemy fleet and let the intelligence report leak out that on such and such a day Archimedes was going to burn up the whole fleet and raise the siege? One can imagine what the effect was on the sailors and officers of the fleet, including Marcellus himself. Archimedes’ strategy might have prolonged the defense through a great part of the two years in which the city resisted. The main problem, of course, and suspicion in the minds of the enemy was--could Archimedes actually burn the fleet with his mysterious mirrors and lenses? (Illustration facing page 32.) The possibility of actual use of the Burning Glasses to start fires on the ships of an invader was not entirely dismissed by Athanasius Kircher who made a special trip to Syracuse in 1636 to study the problem on the spot. He wrote in the same book in which the magic lantern is described that he had constructed a burning glass or lens which started a fire at a distance of 12 feet and that a friend of his, Manfred Septal, on February 15, 1645, shortly before Kircher’s book was completed, had started a fire at 15 paces. Kircher did not believe burning glasses could be used to start a fire at a great distance as claimed by some scientists and experimenters. He said that Cardano’s story of burning at 1,000 paces was ridiculous, as were exaggerated claims of Porta. But Kircher did point out that there may be something of truth in the original story of Archimedes because, in his opinion, ships of the attacking force would be anchored just off the walls of the city, perhaps only 25 to 50 feet away. This was done so the full force of the fleet’s armament of the day could be thrown against the defenders on the walls and yet the men of the ships would be out of range of hand-to-hand encounters with the Syracusans. Kircher reasoned that a great Burning Glass could start a fire in a ship right under the walls of the city if the glass were mounted on top of a nearby building. It is likely that at the most Archimedes would have been able to start only a small fire on the sail of one of the enemy’s ships.