Brick 51 Brick "I shall first treat of bricks, and the earth of which they ought to be made. Gravelly, pebbly, and sandy clay are unfit for that purpose; for if made of either of these sorts of earth, they are not only too ponderous, but walls built of them, when exposed to the rain, molder away, and are soon decomposed ... They should be made of earth of a red or white chalky, or a strong sandy nature. These sorts of earth are ductile and cohesive, and not being heavy, bricks made of them are more easily handled in carrying up the work." Marcus Vitruvius Pollio, De Architectura, Book II, Chapter 3 Mesopotamia were also built of mud bricks, which were much used in ancient Egypt and India. Mud-brick construction is still current in warm-climate areas such as Africa, on the Danube in Europe, and in India where it is said that over half the country's current construction uses mud bricks. 7 In the Americas, mud-brick construction is called "adobe." The fired brick dates from about the third millennium BC, and was later used by the Romans. The main types of fired brick used in modern construction are: · clay; · calcium silicate; · concrete; · slag; and · terracotta and faience. Bricks are an ancient building material, and are most commonly made of clay and water. Originally they were baked by the sun. They are blocks, usually small enough to hold in one hand, which are mortared and laid in a bond pattern. Both the bond and the mortar hold them together. Mud bricks date from Neolithic times in the Middle East (8,000­10,000 years ago), and the buildings of the first ancient settlements, such as Çatal Hüyük in Anatolia, were built from sun-dried, clay-mud brick. Often straw