By his proficiency in the "Equilibrium of Bodies in Fluids," he detected the true weight of Hiero's crown, and exclaimed to the startled public, "I have found it! I have found it!" So greatly was his inventive power feared by the often repulsed Romans, that at last the appearance of a rope or a pole above the wall of a besieged city threw them into a panic, for fear of some new "infernal machine." His burning mirrors occasioned Lucian to say that Archimedes, by his mechanical skill, burnt the Roman ships. Galen refers to the same fact. Archimedes lent great aid in the final defense of his beloved Syracuse, but the fortune of Rome was overwhelming at last. It is said that Marcellus gave strict orders to preserve a person of whose genius he had seen such extraordinary proofs, but this was forgotten in the license of war. A ruthless soldier burst upon the venerable philosopher absorbed over a diagram, and smote him dead. Cicero, traveling in Sicily about a hundred and fifty years later, had great difficulty in finding his tomb. "I recollected," he says, "some verses which I had understood to be inscribed on his monument, which indicated that on the top of it there was a sphere and a cylinder. On looking over the burying-ground (for at the gate of the city the tombs are very numerous and crowded), I saw a small pillar just appearing above the brushwood, with a sphere and cylinder upon it, and immediately told those who were with me, who were the principal persons in Syracuse, that I believed that to be what I was seeking. Workmen were sent in with tools to clear and open the place, and when it was accessible, we went to the opposite side of the pedestal; there we found the inscription, with the latter portions of the lines worn away, so that about half of it was gone. And thus, one of the most illustrious cities of Greece, and one formerly of the most literary, would have remained ignorant of the monument of a citizen so distinguished for his talents, if they had not learnt it from a man of a small Samnite village."