Foundry, an establishment for casting. Casting consists in pouring a molten metal into a suitably shaped mold in which it cools and solidifies, thus forming a metallic figure of the shape of the mold. Metal-casting is as old as civilization, but it has been greatly developed in very recent times. Most metals can be cast, but iron, brass, bronze, zinc, aluminium and type-metal are the metals most used for casting in the industries. The molds are formed of loam, molding-sand, plaster of Paris or metal. In type-founding, steel molds are used. To form a mold in loam or sand requires a pattern. This pattern is usually of wood, but may be of metal. Pattern-making for casting parts of machinery forms a special trade. Iron is melted for casting in a furnace called a cupola. The principle of foundry-work is simple, but the practice of it requires much skill and special knowledge, and special treatises must be consulted for details of the work of a foundry.