Show artillery before the advent of gunpowder the roman ballista was much like the roman catapult it consisted of 0 a trough mounted in a frame in which ropes or skeins of 0 animal skins wora were twisted with sticks the ends of the sticks were joined with a thong and the spring in the twists served as the spring or propelling force the missile consisting of a log beam or stone was wag put la in the trough and the bowstring bow string was drawn back and released to hurl the missile the ballista was used to hurl heavy material for demolishing walls it was primarily a siege weapon the trough was so BO arranged that it could be elevated to lengthen the range and traversed to change the direction of the missile roughly the roman catapult shot heavy snows for effect on personnel and corresponded to the modern light field gun while the ballista fired heavy projectiles and corresponded to modern heavy field artillery |