Perfect Spheres
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Perfect Sphères Manufacturing perfectly round geometrical shapes from solid materials requires spedalized techniques and careful craftsmanship. Humans first "mass-produced" crude sphères as projectiles to be thrown in siège machinery; later thèse sphères became smaller and better shaped as ammunition in weapons and, in the industrial âge, as bearings in machinery. Recently, on flights of the space shuttles Columbia and Challenger, microgravity experiments with the Monodisperse Latex Reactor produced millions of identical perfect sphères only 10 micrometers across. Though darts and arrows had been used as projectiles for centuries, they proved to be balristically unsound when launched from a firearm. The next alternative was round shot, spherical ammunition that remained the most popular type of projectile until the 19th cenrury, when rifled gun barrels came into use. The first spherical projectiles fired with gunpowder were made of stone, which was readily available everywhere and had previously been used in the catapult and the ballista as far back as Roman days. The first références to stone ammunition sphères can be found in France in 1346, in Italy 18 years later, and in England 12 years after that. Making the stone sphères was
painfully slow; craftsmen chipped away with hammer and chisel for hours on a rough block until it became somewhat round. Even after the advent of métal shot, though, stone continued to be used because it remained cheaper than expensive iron and bronze, and also because stone shot was lighter than équivalent métal sphères, thereby requiring smaller charges of gunpowder. (This not only proved less expensive and safer, but also increased the lifetime of the fragile cannons of the period.) However, large stone shot tended to break when it struck a stone wall, and so new materials were needed to penetrate défensive walls. Petrarch describes how the Italians began using bronze shot in 1344. At the same rime, soldiers in France were using spherical lead projectiles. Iron shot came into gênerai use for hand and shoulder weapons during the reign of Charles VD3 of France (1483-1498), though it was mentioned as early as 1350. Ail thèse sphères were cast in molds and worked into a reasonably round shape. Over the course of about a cenrury, iron, lead, and bronze sphères were used interchangeably. Hollow sphères of cast iron were filled with gunpowder and fired from cannons as explosive "shells" of métal. The Netherlands and Venice seem to hâve independently developed this idea in the late 14th century. Many other countries rapidly adopted the concept for land battles, though the risks of exploding métal shells were considered too great to be used on a
ship for naval bardes. Despite a successful engagement by the French captain Deschiens in 1690—in which his single ship drove off four British vessels and, later, two Dutch through the use of exploding shells—no other naval commander used cast-iron shells until 1788, when Sir Samuel Bentham (formerly of England, and then working in the service of the
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