A. Hamilton Thompson, Military Architecture in England During the Middle Ages
“ The tension released, the javelin was discharged. While the ballista could be discharged with a definite aim, the aim of the stone-throwing machine could be only general, and its chief use was to cast stones which, by their elliptic flight, dropped inside the walls of the besieged place.91 Engine for shooting javelins Stone-throwing engineThe ballista, which was simply a huge bow, capable of shooting enormous bolts by the tension of a horizontal cord, was developed upon a small scale into the cross-bow or arbalast, which could be carried and managed by one man. ”
