Or we might see moving up on wheels a shed, from the open front of which protrudes the great iron head of a ram affixed to a huge beam. If you were under the shed, you would see that the beam was perhaps as much as 60 feet in length, and that it was suspended on chains or ropes by which it could be swung, so that the head butted with a deadly insistence upon the masonry of the wall. Meanwhile the enemy from the ramparts are doing their best to set the shed on fire, to break off the ram's head with heavy stones, to pull it upwards by a noose, or to deaden the effect of the shock by lowering stuffed sacks or other buffer material between it and the wall. At another point, in place of the shed, there is rolled forward a lofty construction like a tower built in several stories. When this approaches the wall it will overtop it, and a drawbridge with grappling irons may be dropped upon the parapet. Elsewhere there is mining and countermining. From a safer distance the artillery of the time is hurling its formidable missiles. There is the "catapult," which shoots a giant arrow, sometimes tipped with material on fire, from a groove or half-tube to a distance of a quarter of a mile. The propelling force, in default of gunpowder or other explosive, is the recoil of strings of gut or hair which have been tightened by a windlass. There is also the heavier "hurler," which works in much the same manner, but which, instead of arrows, throws stones and beams of from 14 pounds to half a hundredweight, doing effective damage up to a distance of some 400 yards. [Illustration: FIG. 108.--AUXILIARY CAVALRYMAN.]