The cestros was a novel invention, made during the war with Perseus. This weapon consisted of an iron bolt two palms long, half of which was spike, and half a tube for the reception of the wooden shaft which was fixed into the tube, and measured a span in length and a finger-breadth in diameter. At the middle point of the shaft three wooden “plumes” were morticed in. The sling had thongs of unequal length, and on the leather between them the missile was loosely set. When the sling was being swung round, with the two thongs taut, the missile kept its place; but when the slinger let go one of the thongs, it flew from the leather like a leaden bullet, and was projected from the sling with such force as to inflict a very grievous wound upon any one whom it hit.