The bodies of deceased were buried far away from any village in wood coffins, except for kings, who were placed in large stone coffins after being wrapped in linen. Buried with them were a few personal items, such as copper daggers, flat copper axes, and awls [small pointed tool for piercing holes in leather, wood, or other soft materials.]. The deceased was buried in a coffin with a stone on top deep in the earth to keep the spirit of the dead from coming out to haunt the living. It was learned that tin added to the copper made a stronger metal: bronze. Stone hammers, and bronze and iron tools, were used to make cooking pots, weapons, breast plates, and horse bits, which were formed from moulds and/or forged by bronze smiths and blacksmiths from iron extracted from iron ore heated in bowl- shaped hearths. Typically one man operated the bellows to keep the fire hot while another did the hammering. Bronze was made into sickles for harvesting, razors for shaving, tweezers, straight hair pins, safety pins for clothes, armlets, neck-rings, and mirrors. Weapons included bows and arrows, flint and copper daggers, bronze swords and spears, stone axes, and shields of wood with bronze mountings. The bows and arrows probably evolved from spear throwing rods. Kings in body armor fought with chariots drawn by two horses. The horse harnesses had bronze fittings. The chariots had wood wheels, later with iron rims. When bronze came into use, there was a demand for its constituent parts: copper and tin, which were traded by rafts on waterways and the sea. When iron came into use, there were wrought iron axes, saws, adzes [ax with curved blade used to dress wood], files, ploughshares, harrows [set of spikes to break clods of earth on plowed land and also to cover seed when sewn], scythes, billhooks [thick knife with hooked point used to prune shrubs], and spits for hearths. Lead was mined. There was some glassmaking of beads. Wrought iron bars were used as currency.