ABSTRACT
Although the Chinese vigorously guarded the recipe, gunpowder, called “Chinese snow,” had spread to the West and south India by the thirteenth century, along with fireworks. In 1242, the English friar and scientist Roger Bacon published the formula for gunpowder. By the middle of the century, Islamic armies were using gunpowder against the Crusaders in Palestine, and their weapons included grenades. Arabs also invented an advanced trebuchet (tray-boo-shay)—a medieval weapon for throwing large stones-that employed counterweights to hurl missiles and exploding bombs. By 1276, the trebuchet was being used to lay siege to Chinese cities.
