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:''For the Roman general, see Balista. For the Italian actor, see Gigi Ballista. For the sniper rifle, see FN Ballista'' The ballista (Latin, from Greek βαλλίστρα ''ballistra''〔(Ballistra ), Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', at Perseus〕 and that from βάλλω ''ballō'', "throw"),〔(Ballo ), Henry George Liddell, Robert Scott, ''A Greek-English Lexicon'', at Perseus〕 plural ballistae, was an ancient missile weapon that launched a large projectile at a distant target. The earliest mention of ballista in literature occurs in the Bible, as invented and used under the reign of king Uzziah: II Chronicles 26:15: "And he made in Jerusalem engines, invented by cunning men, to be on the towers and upon the bulwarks, to shoot arrows and great stones withal. And his name spread far abroad; for he was marvellously helped, till he was strong." Developed from earlier Greek weapons, it relied upon different mechanics, using two levers with torsion springs instead of a prod (the bow part of a modern crossbow), the springs consisting of several loops of twisted skeins. Early versions projected heavy darts or spherical stone projectiles of various sizes for siege warfare. It developed into a smaller sniper weapon, the scorpio,〔Warry, J. (1995). ''Warfare in the Classical World''. pp 178. Salamander Books Ltd., London: United Kingdom. ISBN 0-8061-2794-5〕 and possibly the polybolos. == Greek weapon == (詳細はAncient Greece was developed from two weapons called oxybeles and gastraphetes. The gastraphetes ('belly-bow') was a hand held crossbow. It had a composite prod and was spanned by bracing the front end of the weapon against the ground while placing the end of a slider mechanism against the stomach. The operator would then walk forward to arm the weapon while a ratchet prevented it from shooting during loading. This produced a weapon which, it was claimed, could be operated by a person of average strength but which had a power that allowed it to be successfully used against armoured troops. The oxybeles was a bigger and heavier construction employing a winch, and was mounted on a tripod. It had a lower rate of fire and was used as a siege engine. With the invention of torsion spring bundle technology, the first ballista was built. The advantage of this new technology was the fast relaxation time of this system. Thus it was possible to shoot lighter projectiles with higher velocities over a longer distance. For an oxybeles, the rules of a torsion weapon demanded that the more energy could be stored, the thicker the prod had to be and the heavier the projectile, to increase the amount of stored energy delivered to the projectile. The earliest form of the ballista is thought to have been developed for Dionysius of Syracuse, circa 400 BC. The Greek ballista was a siege weapon. All components that were not made of wood were transported in the baggage train. It would be assembled with local wood, if necessary. Some were positioned inside large, armoured, mobile siege towers or even on the edge of a battlefield. For all the tactical advantages offered, it was only under Philip II of Macedon and even more so under his son Alexander, that the ballista began to develop and gain recognition as both siege engine and field artillery. Polybius reports about the usage of smaller more portable ballistae, called scorpions, during the Second Punic War. Since these weapons delivered lighter munitions (thus delivering less energy on impact) it is a widely held opinion that they were used more as an anti-personnel role, or to destroy lighter structures. A less accurate weapon like an onager or other single-arm artillery could hit with more force, and thus would be the more useful weapon against reinforced wood or heavy masonry. Ballistae could be easily modified to shoot both spherical and shaft projectiles, allowing their crews to adapt easily to prevailing battlefield situations in real time. As the role of battlefield artillery became more sophisticated, a universal joint (which was invented just for this function) was integrated into the ballista's stand, allowing the operators to alter the trajectory and firing direction of the ballista as required without a lengthy disassembly of the machine. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「ballista」の詳細全文を読む スポンサード リンク
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